It's a huge programme of reform and after the present crisis is past, this is the thing that will dominate the next couple of years

Tony Blair

His comments come despite the decision of the public sector union Unison to postpone a �1m advertising campaign against the government's plans because of the current international crisis.

Labour Party chairman Charles Clarke said that the tone of the conference would be a sombre one in the wake of the US terror attacks.

He said that conference delegates would have the opportunity to debate a statement unanimously agreed by Labour's National Executive Committee (NEC) on the atrocities.

Conference will also debate an NEC statement on the economy.

And union bosses will have the opportunity to voice their concerns over the government's plans on involving the private sector in public services during a debate on Monday.

'Pragmatic approach'

Mr Blair told the BBC's Breakfast with Frost programme on Sunday: "We are dedicated to the public services ... but the systems and structures within which they work require radical change and we have got to do that.

"It's a huge programme of reform and after the present crisis is past, this is the thing that will dominate the next couple of years."

He insisted the government would take a pragmatic approach to involving the private sector in public services, adding that privatisation of the railways had been a "disaster".

Unison's general secretary Dave Prentis said the union shared the public's concern about recent international events, adding the domestic agenda would be "returned to in the autumn".

The union has, however, arranged for uniformed nurses to give "Keep Public Services Public" postcards to delegates arriving at Brighton's train station on Sunday.

A police marksman casts a watchful eye over the venue

As the conference began on Sunday afternoon, the 3,000 delegates held a two-minute silence in memory of all those who died in the US terror attacks.

The prime minister has already announced that the conference will be cut short and that parliament will meet on Thursday so he can bring MPs up to date on the latest developments.

Meanwhile, a massive security operation is under way in Brighton.

The heightened alert after the US terror attacks and a demonstration by anti-capitalist and anti-war demonstrators prompted a huge police presence in the south coast resort.

March

About 1,000 demonstrators marched on the conference building.

There were some scuffles between activists and police as several protesters were arrested after being identified as potential troublemakers.

A similar anti-globalisation protest at last year's Labour conference attracted up to 1,000 people, but did not erupt into violence.

This year, police have for the first time been issued with pepper spray to use on protesters if they get out of hand.

Senior party figures have pledged Labour will not be distracted from democratic debate as the international crisis continues.

Galvanised steel barriers similar to those used on motorways have been built into the roads and pavements to stop hijacked vehicles ramming the conference centre and the city's main hotels.

RAF fighter planes are also on standby to protect the airspace over the town.