A senior director at Boris Johnson’s business and economic unit has been sacked for using racist language during a meeting with colleagues and visitors.

Nick Hoare, a management consultant at the London Development Agency, was fired on Tuesday within hours of using the word “nigger”. Three members of staff lodged official complaints.

He is the latest in a line of managers to depart from the troubled agency under a cloud since Boris Johnson became Mayor of London nearly 18 months ago.

Mr Hoare’s dismissal is particularly embarrassing because one of the agency’s core responsibilities according to its own website is to tackle discrimination and “promote equality and positive community relations”.

John Biggs, a Labour member of the London Assembly, said: “Boris has found himself in deep water with racial insensitivity in the past. This is the right thing to do and it’s good the organisation is responsive to these issues.

“Many Londoners will be deeply offended by this behaviour. It’s right that it should be unacceptable.”

Mr Johnson won office on a campaign pledge to clean up City Hall after claiming it was cloaked in secrecy and cronyism under predecessor Ken Livingstone.

But he has found this harder to achieve in practice. The London Development Agency, created nine years ago, continues to lurch from one crisis to the next even under new executive management.

The latest — the discovery of a £160 million hole in its 2012 Olympics budget — means that public projects worth about £45 million will have to be axed.

The missing money related to the purchase of land for the 500-acre Olympic Park in Stratford, East London. The manager responsible was dismissed but the agency faced serious questions about its accounting practices.

Even in his own close circle, Mr Johnson has struggled to maintain a united front.

Ian Clement, a deputy mayor, was forced to resign in June after it emerged he had misused a corporate credit card and submitted inaccurate expense claims. This month he received a suspended jail sentence of 12 weeks for fraud.

He was the third deputy mayor to leave Johnson’s team. In July last year, Ray Lewis resigned amid allegations of financial irregularities and inappropriate behaviour. A month later Tim Parker stepped down from the role of chairman of Transport for London.

Other notable departures since May last year include James McGrath, sacked as a political adviser after saying older Afro-Caribbean people should go home if they were unhappy living in London, and David Ross, who quit as Olympics adviser after failing to declare his use of Carphone Warehouse shares as collateral against personal loans.

Mr Hoare had been working for the agency for four months on an interim contract managing procurement processes. He previously worked for the Department of Communities and Local Government.

A spokesman for the agency declined to discuss individual details of employment, adding: “All individuals representing the LDA are expected to uphold the highest standards of professionalism in all of their dealings with colleagues and members of the public.”

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