President Chavez was a guest of the mayor in May

Mr Livingstone had hoped to travel to Caracas to sign an agreement that would see London gain cheap oil from the Latin American country.

The trip was cancelled because of "intense pressure" of the Venezuelan presidential campaign.

The Mayor is currently in Cuba, which is hosting the biannual International Olympic Committee Sport for All.

The Venezuelan Foreign Affairs Ministry said: "It is planned that the Foreign Affairs Minister and relevant officials will sign the cooperation agreement in London in the very near future."

'Screw up'

Speaking in Havana Mr Livingstone said: "It's very similar to being in the middle of a General Election where Tony Blair's diary is changing all the time. It's not surprising and was always a risk."

But Liberal Democrat leader on the London Assembly, Mike Tuffrey, described it as "a screw-up of colossal proportions".

He said: "A trip that was billed as going to Venezuela to see Hugo Chavez to broker an oil deal has resulted in the Mayor of London having to return home early with his tail between his legs because his new best friend won't see him."

The trip was aimed at building links developed in May when Mr Chavez visited City Hall.