Britons' weekly spending was broadly flat in real terms last year, with transport costs eating up the biggest chunk of family budgets, official data showed on Tuesday.

The average British household spent 474 pounds a week in 2010, up from 455 pounds in 2009, according to the annual family spending survey by the Office for National Statistics (ONS), which polled 5,260 households.

In absolute terms, weekly expenditure reached a level slightly above that recorded in 2008 after a fall in 2009.

However, inflation rose at a similar rate last year.

If you do make that adjustment (for inflation), then expenditure in 2010 is actually very slightly lower than 2009, Giles Horsfield, a senior researcher at the ONS, told reporters.

Excluding mortgage interest and mortgage repayments, Britons spent most on transport, with the rise to 65 pounds a week in 2010 from 58 pounds in 2009 driven mainly by spending on fuel. Expenditure on public transport also increased.

Housing costs such as rent, household repairs, utilities and fuels were the second-biggest spending category, followed closely by recreation and culture costs.

A persistently weak British economy and high inflation bode ill for family spending this year.

The OECD forecast on Monday that Britain would suffer a modest recession next year. Adding to the gloom, British retail sales fell at their fastest pace in 2-1/2 years in November, a survey by business lobby CBI showed.

(Reporting by Olesya Dmitracova)