Plans by hundreds of angry protesters to lay siege to the Conservative Party conference in Birmingham have been thwarted.

Police chiefs are refusing to allow a mass demonstration directly outside the International Convention Centre. The Right to Work Campaign, backed by some of the country’s leading trade union officials and MPs including Labour leadership contender Ed Balls, intended to march along Broad Street past the ICC during the opening session of the Tory conference on Sunday October 3.

They wanted to gather in Centenary Square to protest against Government spending cuts at about the same time that Prime Minister David Cameron and the cabinet will be on stage marking the formal start of the four-day gathering.

A claim by the organisers that a route past the ICC and a demonstration in Centenary Square was originally approved before a change of mind by West Midlands Police have been denied.

A police spokesman insisted security fears meant there was never any question of allowing the protest to take place directly outside of the ICC.

The spokesman added: “Police and city council highways officials met with organisers from Right to Work to discuss possible routes for the march which satisfied their stated aims to walk along a high profile part of Birmingham city centre and pass within sight of the ICC.

“It was made clear that any route must also cause the least possible disruption to the city and ensure the safety and security of all protestors, delegates at the conference and other members of the community likely to be affected.

“A potential route was discussed but it was agreed that no final decision would be made until all parties had the chance to review it during a three-day consultation period.”