A new series of the US TV drama 24 - which follows 24 hours in the life of a CIA counter terrorism agent, in "real time" - has been commissioned.

The Fox network will broadcast the news series in the US in the autumn.

The series, shown in the UK by BBC Two, has been a critical success and a ratings hit for the channel.

It has been attracting an average of 2.4 million viewers in the normally quiet 2200 slot on Sundays.

Secrecy

The series, which has already finished in the US, has only reached 4pm on BBC Two - leaving another eight episodes to be broadcast.

Interest in the series in the US reached such a pitch that shooting of the final episode was surrounded by huge secrecy.

The drama centres on agent Jack Bauer, played by Kiefer Sutherland, who will return for the new series.

A BBC spokesman said the corporation is interested in buying the second series, but was unable to confirm any deal.

Clues

The second series will retain the same "real time" format, each 45-minute episode covering an hour in the life of Jack Bauer during a single day.

Few details of the plot of the coming series have been released by Fox.

Viewers of 24 may not want to read on as the following may contain clues as to the ending of the first series.

It has been hinted that a number of key characters will return, including Bauer's daughter Kim, played by Elisha Cuthbert, his secret service colleague Nina Myers, played by Sarah Clarke - and Dennis Haysbert's senator Palmer.

And it is said that Bauer becomes entangled in a plot to assassinate senator and presidential candidate David Palmer.