Wireless Group, the radio business run by former Sun editor Kelvin MacKenzie, yesterday said the relaunch of Talk Radio as an all-sport station had proved a success.

The station, which rebranded as Talksport at the start of the year, generated a 21% increase in revenues during the first six months to £5.1m. The company said male listeners now accounted for 75% of the total compared with 55% at the same time last year under the previous format.

More than £4m spent on advertising the relaunch contributed to losses for the station widening during the first half from £2.9m to £6.5m. That figure was also inflated by £2.2m spent on the acquisition of sports rights, a figure which may raise a wry smile after the station was rebuked for pretending that commentators watching Euro 2000 on a television in a Dutch hotel bedroom were broadcasting live from the games.

In its maiden results as a quoted company, Wireless Group reported revenues of £13.8m up from £4.2m after the acquisition of the Radio Partnership and Independent Radio Group during the second half.

Group operating losses more than doubled to £7.6m due to the cost of relaunching Talksport. Shares in the company slipped 3p to 263.5p against their peak of 289p in July.

Wireless Group, which is the fourth largest radio business in the UK, raised £36m through its flotation in May although much of that cash was used to reduce debt and provide working capital.

The local radio assets moved into the black with a £600,000 operating profit against a £300,000 loss last year.