Brighton and Hove's future as a venue for lucrative political conferences is in doubt after the city economy was dealt a £50 million blow.

The Labour Party yesterday said it would not be bringing its annual conference back to the city for at least five years after this September's event.

The news is a damaging wound to the Brighton Centre's position as a major national venue and has brought about renewed calls for the ageing complex to be urgently revamped.

It has now been overlooked by Labour in favour of Liverpool's waterfront arena, as well as regular conference rivals Manchester and Bournemouth.

The news has been compounded by both the Liberal Democrats and Conservatives confirming they will not be bringing their party conferences to Brighton next year either.

It will be the second time in three years the city has been left without any of the lucrative political events.

The Labour Conference has been held in Brighton seven times since 1997 and on each occasion has been one of the city's highest profile and most valuable events.

Thousands of delegates, party activists, media and other organisations have flocked to the four-day gatherings.

Business leaders estimate they generate more than £10million each time in trade for hotels, restaurants and shops and provides an invaluable advert for the city.

The five years they will be absent will cost local businesses £50million in lost revenue unless replacement events of similar stature can be attracted to the city.

The Brighton Centre's owners Brighton and Hove City Council have been criticised for failing to do more to win selection as host for the conferences.

Conservative council leader Mary Mears yesterday played down the significance of the news.

She said: "Any large conference that we don't get back into the city for a while is a regret for us but we will endeavour to get others. It is only one conference."

Labour had already announced it was taking its conference to Manchester in 2010 but yesterday revealed it would go to Liverpool in 2011, followed by Manchester, Bournemouth, and Manchester again in 2014.

The Conservative Party, which will meet in Manchester in October, plans to go to Birmingham next year and Manchester again in 2011. The Liberal Democrats are in Bournemouth this year and Liverpool in 2010.

Marketing Manchester calculated the Labour Party’s 2006 conference in Manchester generated more than £15m for the region’s economy.

Labour said new host cities gave the party the opportunity to “broaden potential conference venues and the people that attend”.

It also attributed its decision to “state-of-the-art” venues offered elsewhere.

A Labour Party spokesman said: “We expect to return to Brighton in the future, but in the next few years we want to take the opportunity to broaden the range of host cities for annual conference.”

Simon Fanshawe, chairman of Brighton and Hove Economic Partnership, criticised the council's failure to win the conference bid.

He said: "What this demonstrates is that the council needs to get its act in gear. The Brighton Centre is too old and we are losing out to modern conference centres. Why aren't we moving on the Brighton Centre redevelopment quicker? The Conservatives running the council have had more than two years to get on with this and nothing has happened.

"Yet again we are having to ask the council how come they lost an opportunity. We need them not to lose these opportunities."

A council spokesman said redeveloping the Brighton Centre was being constantly worked on as a priority.

It recently announced Make Architects as architects for a £400million redevelopment of the centre and surrounding area.

However the spokesman said no timetable was available for the project.

He said: "The Labour conference is by no means our only conference business. It brings in about £10m to the city, while the council’s conference bureau alone books conferences worth about £50m annually and there is lots more coming in via hotels.

“The biggest conferences are still coming – we have the TUC here in 2011- and the centre will continue doing a roaring trade with other conferences, shows and exhibitions."

Councillor Mears said Labour's decision to look elsewhere may be politically motivated.

She said: "I think it shows Labour know they are finished in the South East."

Amy Kennedy, deputy convenor of the council's Green Party members, made the same point.

She said: "They are retreating to their northern heartlands."

Both Nancy Platts and Simon Burgess, Labour's candidates for the Brighton Pavilion and Brighton Kemp Town constituency, rejected the suggestion.

Mrs Platts said: "These kinds of decisions aren't made on political grounds, they are about facilities and finances. The council leader should be concentrating on fixing the problem here and not scoring cheap political points."

Mr Burgess said Labour were unlikely to be going to Bournemouth if their decision was politically motivated.

He added: "When I was leader of the council two years ago the Brighton Centre plans were moving forward. Progress has been almost invisible since then."