Senior civil servants will be free to retire when they like, the cabinet secretary has announced.

The move brings the senior civil service (SCS) into line with the rest of the civil service following a review by the Cabinet Office.

Sir Gus O'Donnell made the announcement on National Older People's Day, exactly a year after he announced that junior officials would be allowed to work beyond 65 years of age.

Until recently the retirement ages have been left to the discretion of department heads, but Cabinet Office work now means the new rules will come into force across the civil service from April 2010.

Sir Gus said the end to the "artificial and unnecessary cap" was necessary if the civil service wanted to use the "potential of our older, senior civil servants" and provide "greater working flexibility for all civil servants".

The cabinet secretary has always insisted that the government's workforce has to represent the population, and has repeatedly pointed out that the country has to deal with an ageing population.

"Today's move also shows the civil service is committed to using the knowledge and experience of its increasingly diverse workforce to improve the delivery of public services for everyone," he said.

The move has been welcomed by unions. Dave Penman, the FDA's head of operations, said: "We have always said that there is no excuse for treating staff above and below the SCS differently.

"The changes from March 2010 ensure that civil servants of whatever grade can make meaningful decisions on retirement based on their own circumstances, rather than be forced out of employment against their will when they still have a valid contribution to make."