The Financial Services Authority is writing to more than 38,000 people across the UK to warn them that they could be the target of share fraud after it recovered a master list used by boiler room fraudsters.

The list contains the names and addresses of 38,242 people who the FSA believes may be contacted out of the blue and offered worthless shares. The greatest concentration is in London and the south-east, but there are significant numbers in Yorkshire and Lancashire too.

The list is the biggest the FSA has ever recovered and is believed to be still in active use by boiler rooms operating in the UK and abroad.

The list was recovered via the FSA’s intelligence network with its counterparts in the US, with Immigration & Customs Enforcement and the Internal Revenue Service.

The share fraudsters commonly known as boiler rooms contact people by telephone and use high pressure sales tactics to con them into buying non-tradable, overpriced or even non-existent shares.