A new breed of leader has been elected to most of the main unions during the last five years and this spells trouble for Tony Blair.

Whereas many of the old union bosses felt their best route to success was to go along with much of what the Labour Government was doing despite doubts about some policies, their successors have no compunction about challenging Mr Blair and his Cabinet.

This means the Government will have a rough ride on controversial but cherished projects such as private finance initiatives, foundation hospitals and education reforms.

Unison general secretary Dave Prentis was in Brighton yesterday articulating his beliefs to the annual conference.

Mr Prentis was uncompromising but showed some guile in pledging to work within the Labour Party for reform rather than outside it.

As head of the biggest union in Britain, he knows Unison will carry far more clout if it influences the party of Government from inside rather than casting itself into permanent and probably ineffective opposition.