Sir Martin Sorrell, chief executive of ad agency giant WPP, has dropped his heaviest hint yet that yesterday's Budget changes to company taxes will encourage the firm to re-locate back to Britain.Sir Martin told the BBC this morning "There has to be legislation enacted but I think it looks as though we will make that recommendation."Chancellor George Osborne delighted UK businesses with his Budget proposal to cut mainstream corporation tax from 28% to 23% over four years beginning with an immediate 2% cut to 26%.Tax on inter-company loans to overseas subsidiaries has also been slashed, a move seemingly aimed at multi-national firms such as WPP.The ad group shifted its tax domicile to Ireland in 2008 because of the impact of UK taxation on its overseas profits. It makes 90% of its profits outside of the UK. Chancellor George Osborne said: "We have got big companies like WPP coming back to the UK, that is going to help us with the growing economy."pw