Colleagues of Scotland Yard Assistant Commissioner Tarique Ghaffur said he was disappointed his force will not pick up the full bill for mediation.

Commissioner Sir Ian Blair is preparing for last ditch behind-the-scenes talks with Mr Ghaffur to head off an employment tribunal at which he will allege discrimination.

But the Metropolitan Police Authority, the force's board of governors, ruled it will not pay the total costs of talks with an independent mediator, Mr Ghaffur's allies claimed.

The Metropolitan Black Police Association (MetBPA), which is supporting Mr Ghaffur, said any breakdown in talks could lead to expensive court action.

Chairman Alfred John said a lot of work has been done to bring both sides together for mediation to resolve the dispute without recourse to the courts.

But he said: "For mediation to work there has to be equality of arms. The Metropolitan Police Authority seems not to want this matter to be resolved amicably. The cost of full blown court proceedings will be many more times greater and the main losers will be the taxpayers of London, who will have to pay."

Mr Ghaffur sparked a damaging race row last month after it emerged he was preparing to sue his force.

Colleagues said evidence of bullying, discrimination and victimisation against the senior Asian officer is compelling. They said the officer, who is responsible for Olympic security preparations, has been treated "extremely poorly".

Mr Ghaffur was said to have compiled a dossier detailing what he claims is victimisation by Sir Ian and Police Authority chairman Len Duvall. Both men denied in the strongest terms that they have behaved inappropriately in any way.