One of the country’s most senior police officers is picking up a six-figure salary and a full pension after retiring six years ago then returning to work as a chief constable, The Times has learnt.

Ian Johnston, who leads the British Transport Police (BTP) and is a national police spokesman on organised crime, is the highest-paid officer in the country with an estimated pay-and-pension package of £260,000 a year.

By contrast, Sir Ian Blair, the Commissioner of the Metropolitan Police and the country’s highest-ranking officer, earns £234,000.

The disclosure of Mr Johnston’s financial package will reignite the bitter debate over the Government’s refusal to pay rank-and-file officers their full wage settlement.

Keith Vaz, MP, chairman of the Commons Home Affairs Select Committee, which will debate the pay row today, said that he was surprised to learn of the deal. “It will be interesting to know how widespread this practice is,” said Mr Vaz. “I will be writing to the Home Secretary to discover how many people this applies to at the moment. It is news to me and I’m sure it will be of great interest to the committee.”

According to the force’s 2006-07 accounts, Mr Johnston, 62, is paid £190,000-£195,000 by the British Transport Police. He became chief constable of the force in May 2001, the year that he retired as an assistant commissioner at Scotland Yard. The Times has estimated that his annual pension is in excess of £70,000 – two thirds of the salary for an assistant commissioner at Scotland Yard when he stepped down.

During last year Mr Johnston claimed expenses of £6,964.40 – considerably higher than the £5,000 per annum that led to an audit of a senior Scotland Yard officer’s expense claims last month.

Until recently police officers became eligible to retire and receive their pension, at two thirds of their final salary, after 30 years’ service. New recruits must now serve 35 years before becoming entitled to their full pension.

Mr Johnston benefits from the anomalous position of the British Transport Police which, unlike most forces, does not come under the auspices of the Home Office.

His force, which is responsible for policing the railway network across Britain, falls under the control of the Department for Transport and has a separate pension scheme. Mr Johnston is therefore able to collect his full pension from his service at the Met just as he would be if he had retired and taken private sector employment.

It is understood that a number of other senior officers have benefited from the same arrangement – retiring from other forces, collecting their pensions and securing new positions with British Transport Police.

Retired officers are allowed to return to police employment with regular forces after retirement but receive reduced pension benefits. Mr Johnston told The Times that he was entitled to his salary and pension. He said: “I spent 35 years working with Kent and the Metropolitan Police and have earned my pension from that. Now I am working with BTP and am being paid the rate for doing that job.”

In addition to policing the rail network, Mr Johnston is also a lead spokesman for the Association of Chief Police Officers. He represents the police on issues including forensic science, organised crime, drugs, firearms, fraud and violent crime.

Sir Alistair Graham, chairman of the British Transport Police Authority and a former chairman of the Committee for Standards in Public Life, said: “I didn’t recruit the chief constable but he has my full support. The BTP is not like other police forces. We are not a Home Office police service, we are paid for by a levy on the railway industry. The authority is concerned to get the best possible police officer to act as chief constable. We’re satisfied he is that person.

“There is no reason I should be aware of his personal arrangements. Plenty of people take advantage of their position to collect their occupational pension and resume employment elsewhere. It happens in the public and private sectors. It’s not unusual, it just happens in this case that he is a chief constable.”

In 1998 Mr Johnston was chosen by the Met to make its formal apology for the handling of the investigation into the murder of Stephen Lawrence. Mr Johnston joined the Met in 1965. Between 1989 and 1992 he was assistant chief constable of Kent before returning to Scotland Yard as a deputy assistant commissioner.

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