Duke Street

Investing in growth across the U.K. and Europe

High quality mechanical and electrical engineering solutions across Europe

Duke Street

Investing in growth across the U.K. and Europe

A leading medical imaging solutions provider

Duke Street

Investing in growth across the U.K. and Europe

Producer and distributor of gardening products

Duke Street

Investing in growth across the U.K. and Europe

Manufacturer and distributor of generic pharmaceuticals

Duke Street

Investing in growth across the U.K. and Europe

World’s leading provider of escorted rail holidays

Duke Street

Investing in growth across the U.K. and Europe

Premium river cruise operator

Duke Street

Investing in growth across the U.K. and Europe

Plant hire business

Duke Street

Investing in growth across the U.K. and Europe

The UK’s largest indoor go-karting operator

We invest in Western European mid-market companies

At Duke Street, we have been investing in mature, mid-market Western European businesses for over twenty five years. Our investment strategy is concentrated on four sectors: Consumer, Healthcare, Industrials & Engineering and Services. Typically we invest in companies with an enterprise value of between €50m - €350m. Our strategy is based on our ability to identify unique opportunities and add value to each business we acquire. We aim to transform the prospects of the companies that we invest in.

Origination beyond the obvious

We focus our efforts on transactions developed on an exclusive basis. We actively seek complex deals which other investors may avoid if we think they have underlying growth potential.

Value creation

Our mission is to accelerate the growth of the companies that we buy. We help our companies grow both organically and through acquisition.

Supportive Structure

We have developed a robust approach to building relationships between ourselves, the CEOs of our portfolio businesses and our Operating Partners.

Sector focus

We believe sector knowledge is critical, which is why we have dedicated teams focusing on our four core sectors. This, alongside the deep industry experience of our Operating Partners, has allowed us to create a proven track record of successfully building companies.

We invest in companies with strong brands serving consumers across multiple channels

We have extensive experience in the consumer sector: in restaurants with wagamama, in the gaming sector through our investment in companies such as Gala Bingo, Sporting Index and Leisure Link. In leisure, we have invested successfully in both niche hotel operators and fitness and leisure businesses. Two of our investments in particular – SandpiperCI and The Original Factory Shop – display our willingness to back retail management teams with ambitious growth plans, even at a time when the sector as a whole was experiencing tough trading.

We also have a wealth of experience of working with management teams in consumer branded products. At Simple, we backed an ambitious growth plan for the business to become the UK’s leading skin care provider by volume, overtaking companies such as Nivea and L’Oreal in the process.

See our Portfolio for a more in-depth analysis of these and further Consumer investments.

Duke Street is a long-term investor in the healthcare space, making our first investment in 1997

Since then we have deployed c. €700m in the sector, backing great management teams to deliver transformational business plans.

We believe the sector to be structurally attractive: it is defensive and benefits from significant barriers to entry due to the complexity of the products and services involved.

We also believe that it lends itself well to our investment strategy. Europe is home to a large number of strong management teams, and high value-added businesses which deliver outstanding patient outcomes. Such businesses typically offer multiple routes to value creation. Even the most mature sub-sectors remain fragmented and so there is significant potential for buy and build.

Please see our Portfolio for a more in-depth analysis of our past and present Healthcare investments.

We cover a broad range of Industrials sub-sectors with a particular focus on aerospace & defence, engineering, manufacturing & security

We look to invest in companies with differentiated product or process IP, operating in attractive end-markets, with scope to affect operational transformation through inter alia, a build-up in specific niches, technological changes, or product / geographic diversification.

We back management teams with a clear strategic vision as well as a strong operational focus; and our in-depth understanding of the sector means we are well-placed to work in partnership with such teams.

Our investments in this sector include Deloro Stellite, the specialist engineering group, and filtration solutions provider Madison Filter. See our Portfolio for a more in-depth analysis of these and further investments.

We invest in services businesses with the potential for operational improvement and rapid growth

The services sector encompasses a wide range of sub-sectors, each subject to its own dynamics but often with outsourcing as a key driver. We identify macro trends that will drive above average market growth, and then back businesses providing value added skills and products to their customers in those markets. We are particularly attracted where there is the potential for operational improvement as well as organic growth. We partner with best-in-class management teams providing support, capital and expertise where this is required and materially adds value.

We have considerable experience in the sector, complemented by a large network of industry contacts. Investments we have made in this sector include Ardent Hire Solutions, a heavy equipment hire business, Payzone, a consumer payments business, and the specialist pensions group Xafinity. See our Portfolio for a more in-depth analysis of these and further Services investments.

Responsible Investing

ESG Considerations

At Duke Street we consider environmental, social and governance (ESG) issues throughout the investment decision-making process and life-cycle. We believe that robust and well-implemented ESG policies and practices contribute directly to the long-term success and sustainability of our portfolio companies. Implemented effectively, they help us to protect and enhance reputation and financial performance whilst creating stronger, more valuable companies which can create benefits for all stakeholders: from employees to customers, suppliers to shareholders, and the wider community at large.

We review our approach to ESG regularly to ensure that it continues to reflect best practice.


Initiative Climat International

As part of our commitment to actively address climate risks, Duke Street is a signatory to the Initiative Climate International (iCI), a global private equity initiative focused on cross-sector collaboration to develop pragmatic solutions to address climate change and, in particular, reduce carbon emissions of portfolio companies. iCI is endorsed by the UN-sponsored Principles for Responsible Investment (PRI).


As responsible investors we aim to minimise our environmental impact by ensuring efficient resource use in energy, water usage, recycling and reductions in greenhouse gas emissions.


We take our role as fiduciary guardian of our investors’ capital seriously and believe that strong corporate governance is essential to the financial integrity and success of our firm. Our investment committee oversees all investment decisions and we have put in place practices to ensure that we and our portfolio companies comply with all relevant corporate governance policies and procedures.


We aim to maintain a positive working environment both at Duke Street and portfolio company level by promoting diversity and inclusion and ensuring compliance with all employment legislation.


With careful consideration to all environmental, public health, safety and social issues we build better, more sustainable brands which benefit both Duke Street investors and the wider community in which our businesses operate.

Find out how Duke Street portfolio companies make responsible investing a reality.

Our Portfolio

Madison Filter Solutions

SECTOR: Industrials & Engineering

Filtration solutions provider serving niche global markets

Often the companies we invest in are the unloved subsidiaries of much bigger businesses. We invest in them because we can see the potential for a genuine and rapid transformation of the company and spot management teams with vision and ambition. In the case of Madison Filter, here was a company that was operating as a mini-conglomerate with a CEO who knew what it would take to turn the company around. Out of it we created and sold three credible and focussed businesses.

Backing ambitious managers

Madison Filter (formerly the Special Materials Division of Scapa Group plc) was in the middle of a significant turnaround and restructuring programme when we acquired the company in November 1999. Chief Executive Richard Stephenson had spent the previous two years downsizing the business to dispose of low-margin and loss-making product lines. He was now keen to find a partner to support his plans for the future.

With our backing, Madison Filter was transformed from a company manufacturing several different filtration products for a number of disparate industries into the world’s leading manufacturer of oil screens.

Learning about a new industry

Stephenson started the programme of downsizing when Madison’s parent company identified the division as non-core. As a result, sales fell by 19% and EBITDA by 50% between 1997 and 1999.

We had a lot of work to do. Having recognised that the company provided an ideal platform for an international Buy and Build strategy in the filtration media sector, we were willing to commit significant time and resources to the opportunity.

In a short space of time we conducted extensive due diligence on the industry, Madison’s product portfolio, and its primary markets. We then worked hard to really understand Madison’s consolidated numbers until we were happy we could agree with management’s view that the business was indeed poised for a turnaround.

A complete transformation

At the time of acquisition, Madison Filter designed and manufactured consumable filtration media for the oil and gas, chemicals, water treatment, and pulp and paper industries. The company also had a small operation making a highly engineered polishing belt used in the production of silicon microchips and semiconductors.

We supported a Buy and Build strategy, alongside piecemeal disposal in order to maximise value.

In July 2000 we backed Madison’s acquisition of Southwestern Wirecloth, making the company global leader in the manufacture of oil screens. The acquisition transformed Madison, and led to a formal division into three business lines: oil and gas filtration, general industrial filtration, and polishing belts.


Towards the end of 2001, amid a slowing economy and great uncertainty, we successfully sold both the oil and gas and general industrial filtration businesses to trade buyers in the US and Continental Europe. With improved market share, a portfolio of new products, and a focus on filtration solutions, the companies will be of significant value to their new trade owners.

The semiconductor polishing belt business was sold to Praxair in September 2002.

Our Team

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The Duke Street investor base comprises traditional funds and pools of committed capital alongside co-investment mandates from high quality investors, which include Fund of Funds, Pension Funds, Insurance Companies and Family Offices amongst others. Our investors are long-term supporters of the Duke Street investment model and are located across the globe with substantial support from North America and Europe.

Duke Street has invested over €3bn in more than 50 companies over the last 25+ years and has achieved strong returns in excess of 25% IRR throughout the cycle. Duke Street is an independent sponsor and itself invests substantially in each deal, ensuring maximum alignment between Duke Street, its investors and management teams.

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Duke Street

Nations House,
103 Wigmore Street,
London W1U 1QS

Tel: +44 (0)20 7663 8500
Fax: +44 (0)20 7663 8501

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