The crash of MG Rover and weak new car sales figures have helped shove in-car navigation specialist Trafficmaster off-track.

The company swung into a loss at the half way stage, partly due to what it called "disappointing" Smartnav sales.

Chief executive Tony Eales said the company wrote off £563,000 following the collapse of MG Rover.

Trafficmaster had a contract to supply its Smartnav satellite navigation system as standard to MG Rover's 75 and MG ZT.

For the six months to June 3, the group recorded a pretax loss of £475,000 against a profit of £3.5 million a year earlier on sales of £19.7 million, up 16 per cent.

The first half, it said, was "mixed", with strong performances in Teletrac and Trackstar offset by weaker than expected Smartnav sales.

It added: "We consider Smartnav's performance disappointing and will be taking action to improve the return from this business."

Smartnav unit sales were 16,500 in the period, up 55 per cent on last year. Both Teletrac and Trackstar performed well, the group said. Teletrac recorded a 28 per cent increase in US dollar revenues to £18.1 million while Trackstar grew by nine per cent.