Three Midland-based directors of engineering Alstom firm have been arrested in a corruption investigation amid claims of bribery.

The Serious Fraud Office (SFO) revealed raids took place on addresses in Warwickshire, Staffordshire and Shropshire on March 24, and the men, aged 52, 51, and 44, were brought in for questioning.

They were arrested on suspicion of bribery and corruption, conspiracy to pay bribes, money laundering and false accounting.

The arrests followed a raid on Alstom offices in Ashby-de-la-Zouch and Rugby, and other raids took place at addresses in Cheshire, Derbyshire and London.

The investigation centres on suspected bribes paid in the UK to influence the awarding of overseas contracts to companies in the Alstom group, which supplies into the energy sector around the world.

Police offices from several UK forces and the Swiss Federal Police have been involved in the investigation, which was code-named Operation Ruthenium in the UK.

SFO director Richard Alderman said: “The SFO is committed to tackling corruption. We are working closely with other criminal justice organisations across the world and are taking steps to encourage companies to report any suspicions of corruption, either within their own business or by other companies or individuals.”

The operation involved 109 SFO staff and 44 police officers and financial investigators.