Change tax laws on overseas income, says WPP

WPP, led by Martin Sorrell, moved its tax base to Ireland over 18 months ago in protest at what it estimated as tens of millions of pounds of additional taxes due to changes to the tax regime on overseas profits.

"We will have to see what the result is," Mr Sorrell said. "One of the complications is that any future government could then change that legislation, but on the assumption that the appropriate guarantees could be given, then yes we would (return)."

WPP conducts most of its business outside the UK.

The opinions of Britain's business leaders have become a key factor in the build-up to the General Election on May 6 as the Labour party and Conservatives seek to persuade the electorate they have the best ideas to help the economy grow after a sharp recession.

The Conservatives, who have seen their lead in the opinion polls slip, said they wanted to reform the corporate tax system as part of a drive to prevent companies from moving offshore.

The Labour government has also launched a consultation aimed at giving companies more clarity on any likely changes to tax laws in its bid to persuade multinational firms the UK remains a competitive place to locate.