2015 was a record year for new car registrations.
The total exceeded 2.6 million units for the first time and the year-end means four years of consecutive growth.
The market has posted increases in all bar one of the past 46 months.
Last month was the biggest December ever - up 8.4% - with 180,077 new cars registered, according to figures released today by the Society of Motor Manufacturers and Traders.
Overall, the market rose 6.3% in 2015 to 2,633,503 units – exceeding forecast and outperforming the last record year in 2003 when 2,579,050 new cars were registered.
This is only the fourth time that the market has surpassed 2.5 million vehicles in a full year.
There was growth across all sectors, with UK fleets boosting demand by 11.8% to reach an all-time high of 1.3m units.
The private sector was up 2.5%.
Gains were reported across all fuel types, with petrol and diesel registrations up 8.4% and 3% respectively with equal market shares.
Alternatively fuelled vehicle (AFV) demand, meanwhile, grew 40.3%, securing the biggest ever market share of 2.8% for a year.
Plug-in hybrid volumes more than doubled, while pure electric vehicles saw an uplift of around 50%.
Mike Hawes, SMMT chief executive (pictured), said, “The new car market defied expectations in 2015, hitting an all time record driven by strong consumer and business confidence.
“Buyers took advantage of attractive finance deals and low inflation to secure some of the most innovative, high tech and fuel efficient vehicles ever produced.
“The past four years have seen a remarkable period of sustained growth, and the outlook remains positive with every reason to expect the market to hold broadly steady in 2016.”
Sue Robinson, director of the National Franchised Dealers Association, said: “Strong new car sales like this will have a lasting positive impact on the UK economy as all the new cars of today need to be serviced in the years ahead.
"This is also a positive indicator for the UK job market, with 500,000 people in the UK employed in services cars, relative to the 200,000 employed manufacturing them.”
Rupert Pontin, Glass's head of valuations, said: “As predicted by Glass’s over a year ago, 2015 new car registrations have exceeded 2.6m units which is fantastic news for the industry and demonstrates the strength of the UK market at this point in time.
"Growth will continue through 2016 and Glass’s expect a 3% increase during the course of the year as the economy continues to grow and consumer confidence extends further.
"Total registrations for this year will be in the region of 2.71 million and the growth is likely to be driven by ever more appealing PCP schemes.
"The one word of caution is that as an industry we need to understand the impact of pre-registration and the effect it may have on used car values during 2016.”
New car registrations - rolling year totals, 2009 - 2015
New car registrations by type for December and full-year 2015