Several African countries have pulled out of pre-Olympic training camps in Britain at the last minute because they are unable to pay the fees. Senegal, Uganda, Guinea-Bissau, The Gambia and Mozambique are among the nations which have reneged on agreements to use the UK's training facilities before the Games.

Locog, the Games organisers, pledged to pay up to £25,000 to any Olympic or Paralympic team who did their training in the UK, but were prepared to pay out only afterwards. This has left poorer nations struggling to find the funds up front.

The lost time acclimatising to British weather and the missed opportunity to use international-standard facilities could put them at a disadvantage to other athletes. The no-shows will also be a blow to Locog, who planned the camps around Britain to help spread the legacy of the Games beyond London.

The Ugandan team were meant to be in Coventry before the Games but will now go straight to the Olympic Village on 22 July. A spokesman said: "There would have been a lot of expense involved… They all wanted to go to Coventry."

Gambian athletes had been expected in York, but Momodou Demba, chef de mission at Gambia's National Olympic Committee (NOC), said: "Unfortunately it did not work out… Locog promise to take care of the bill, but the fact that we would have to put up the money first then be reimbursed does not go down well. It's quite expensive."

Burundi never took up the offer of a British training camp because they knew they would not have the funds. Tharcisse Harerimana, executive secretary for the Burundi NOC, said: "If Locog had paid in advance then we could have come, but we had a meeting with them and they told us it was not possible to have this money."

Paralympic teams from Niger, the Central African Republic, The Gambia and Ghana are also understood to be abandoning pre-Games training in Britain for funding reasons.

A spokeswoman for Locog said: "We've always made it plain we'd pay at the end so it eliminates fraud and accusations of impropriety."

By Emily Dugan & Denise Roland