The UK contractor said the deal would give it access to major German corporate clients, complementing it existing German operations for mainly anglo-saxon multi-nationals.

Tecton was established in 2000 and achieved a £7m turnover last year specialising in office fit-out and facilities management based in Cologne and Berlin.

Managing director, Christoph Eckes, who will retain his 10% stake in the firm and will continue to manage the business, which employs 13 staff and made a profit of £700,000 in 2012.

The vendor, Daniela Woell, will be exiting the business and her husband, Frank Woell who established the business, will remain as a consultant for two years.

Its clients are predominantly insurance and investment companies who are owners of German commercial office real estate, including IVG, MEAG, Talanx, AXA and German blue chip international businesses such as Deutsche Bank, RWE and Bayer.

David Lawther, Chief Executive Officer of ISG, said: “The Tecton acquisition is part of our strategy to continue to invest in overseas markets and to build scale in our key international locations.

“Tecton’s largely German customers will widen our client base in Germany and allow us to offer ISG’s wider service offering to these customers.”