Car sales website Auto Trader boosted its half year profits as a growing UK economy helped new and used car sales.

The firm, which attracts around 43 million visits to its websites a month, said its underlying operating profit jumped 17% to £83 million in the six months to September 27 compared to a year ago.

It added the number of online advert views per month lifted 9% to 240 million, while the average revenue it received from car forecourt retailers also rose 9% to £1,347 per month. Shares lifted 3%.

The company, founded in 1977 as a classified ad magazine, floated on the London Stock Exchange in March at 235p a share, valuing the business at £2.35 billion.

UK car sales in October fell 1.1%, according to data from the Society of Motor Manufacturers and Traders (SMMT) earlier this month. However, this was the first fall since early 2012.

SMMT chief executive Mike Hawes said: “The UK car market has gone through a period of unprecedented growth and, so far, 2015 has been a bumper year with the strongest performance since the recession.

“As expected, demand has now begun to level off but the sector is in a strong position, as low interest rates, consumer confidence and exciting new products combine to attract new car buyers. The current full-year growth forecast remains on track.”

Auto Trader was known for its magazine full of used-car adverts but it began to go online from 1996 and the final publication of the print magazine came in June 2013.

In the mid-90s the group diversified into a number of foreign markets including Holland, South Africa and Italy. But in 2013 the business sold off most of its overseas operations and now focuses on the UK and Ireland.

Auto Trader chief executive Trevor Mather said: “We believe there is substantial opportunity to grow the business based on the increasing importance of the internet for automotive advertising, and the growing use of data to improve the efficiency and effectiveness of the industry.”

Analysts at Numis added: “Auto Trader has reported strong interims, that are ahead of our expectations in all areas.”