This follows June 2003 which rose 15.8 per cent on the previous year. This year's total was 23,752 units above the third highest June total and just 1,097 units below last year's record.
The Society of Motor Manufacturers and Traders says the strong June performance left registrations in the first half of 2004 up 2.2 per cent at 1,376,567 units and on course to hit SMMT's full year forecast of 2.6m units.
Diesel registrations in June account for 32.2 per cent of all new cars sold.
SMMT chief executive Christopher Macgowan said, 'In a fiercely competitive market, with some excellent new models, sales remain up over the year to date. Last month saw a slight decline following a record total in June 2003.
'June 2004 was still the second highest on record. Despite fuel price concerns and rising interest rates we have seen a record first six months of 2004. Consumer confidence remains strong and we should see 2.6 million new cars leaving showrooms by the end of the year.'
The Renault Mégane was the top selling diesel model in June - the first time since November 2003. Over the first half of the year the Ford Focus remained the top diesel model, just ahead of the Mondeo.
Within the overall market place, the Focus also topped the first half and June registrations – outselling all other ranges by some 35 per cent.