Trade unions yesterday called on three of London's top jewellery retailers - Asprey, Harrods and Leviev - to sever all trading links with Burma following EU trade sanctions announced earlier this week...The TUC [Trades Union Congress] said yesterday that seven UK-based companies that have previously traded with Burma in products covered by the sanctions...They included three small timber companies and a mining finance house, as well as the three jewellers...Harrods said last night: "Needless to say, Harrods does not purchase rubies itself, some of which do indeed emanate from Burma...Asprey said: "We have never bought any stones/jewels directly from Burma and our suppliers no longer deal with Burma as far as we are concerned...Leviev said,..."Leviev will issue a letter to Guy Rider, the [TUC] general secretary, to confirm that Leviev has no business links to Burma..."