Labour's biggest single financial donor will today urge the party's MEPs to think again about their support for the "economically disastrous'' European Services Directive.
Derek Simpson, general secretary of the Amicus union, will tell the Labour representatives in Brussels that the legislation would be "extremely dangerous'' for British companies.
Mr Simpson, other union leaders and some major employers believe that the directive in its current form will give a massive competitive advantage to companies from other European Union countries providing services in Britain.
The proposed legislation, which is due to pass through its crucial first reading tomorrow, will enable businesses registered in other EU countries to ignore minimum wage and health and safety law in the UK. The Bill will allow a foreign service provider to apply employment law enacted in its country of origin.
Amicus believes that the votes of 19 Labour MEPs will be critical to the passage of the statute.
Mr Simpson said: ""It would be a disappointment if a Labour Government supported this directive in its current form. It would be a government presiding over the euthanasia of the UK's best jobs, turning us into a Third World economy.''
The union points out that under the directive's "country of origin principle'' foreign businesses would not have to apply a range of British legislation, including laws on health and safety, the behaviour of the company, the quality and content of the service, the technical and financial capacity of the organisation and the payment of fiscal and social charges.
Amicus believes the long-term consequence of such legislation would be the eradication of all local measures to protect against potential abuses and to ensure a decent standard of services.
Mr Simpson points out that the foreign workers posted to this country will have their terms and conditions of employment monitored by their own governments. It would enable companies registered outside Britain to circumvent trade union representation and collective agreements.
Members of Amicus and other unions from across Europe plan to demonstrate against the directive in Strasbourg on 14 February.