A surprise visit to Cuba by London mayor Ken Livingstone has attracted fierce criticism.

The London mayor's office said he would attend a sports conference in Havana on "Olympic related business".

But the 11th World Sport for All Congress, sponsored by the International Olympic Committee (IOC), ended at noon on Friday.

As the mayor only arrived in the Caribbean on Thursday, it gave him just three hours to attend seminars with little apparent relevance to the London 2012 Games.

According to the congress programme, Friday's main topics include jargon like, "Building strategic coalitions in promoting physical activity in an ecological approach."

Among the more obscure items are sports events in Slovenia, mass community recreation in Venezuela and the physical abilities of Cuban children.

The big question is whether the mayor, nicknamed "Red Ken", will meet the sickly Cuban president Fidel Castro.

Critics also asked whether Mr Livingstone would see IOC president Jacques Rogge, who attended the conference, over the remarks made by London's former Olympic boss.

Earlier this week the American construction tycoon Jack Lemley resigned as chairman of the Olympic Delivery Authority because he feared the massive projects would come in late and over budget.

Mr Livingstone's unexpected Cuban stopover is part of a week-long trip around South America.

It was known that he would visit President Hugo Chavez in Venezuela in return for his trip to London earlier this year, but the Cuban leg only came to light when the mayor mentioned it to BBC radio on Wednesday night.

According to the mayor's office, he is due in Caracas on Monday. In the meantime, he had "a full programme of meetings" with Cuba's Olympic leaders, Havana mayor Juan Cortino Aslan and government members, his spokesman said.

Mr Livingstone was invited to the conference by Lord Colin Moynihan, the chair of the British Olympic Association.

But Angie Bray, leader of the London Assembly Conservatives, said: "Why only turn up on the last day?

"It would also be interesting to know what Jacques Rogge thinks about the recent criticisms by Jack Lemley of the progress of the 2012 Games, were that the reason the Mayor was travelling."

However, Ms Bray said the trip must have been "well planned in advance" as Cuban visas were hard to get and several staff were accompanying the mayor.

"Could this just be an excuse, en route to Venezuela, to visit the last remaining bastion of 20th Century Marxism, and maybe also the gravely ill Fidel Castro?"

Mr Castro would be "an ideological hero" to some of the mayor's leftist advisors, she added.

"One can only wonder as there seems to be little benefit to Londoners from this trip, only a great deal of expense."

Mike Tuffrey, the Liberal Democrat leader on the London Assembly, labelled the trip "a smack in the face to London's council taxpayers".

The mayor was "a man who professes to know little about sport", yet he used "an IOC sponsored event as a ticket to ride", Mr Tuffrey said.

However, the mayor's spokesman said Cuba played a "central role in the international Olympic movement".

"Its Olympic achievements, in fields like boxing, are legendary and out of all proportion to its size and population," she added.

"As the host city for the 2012 Games, London has to develop close relations with other key Olympic players."