Christmas shopping online in the UK will peak on 8 December but growth in festive spending on the internet is set to slow, a report has predicted.IMRG and Capgemini estimate £320m will be spent on the internet on 8 December with the peak between 1pm and 2pm.It forecast that UK shoppers will spend £13.16bn online in the final quarter of 2008, some £215 each.This was 15% higher than the same period a year ago, but the growth is down from a 54% rise a year ago."Retailers and suppliers will be under extreme pressure to price competitively this year," said IMRG chief executive James Roper.Some 42% of sales on 8 December will take place outside of traditional shopping hours, either before 9am or after 6pm, the report said.The predictions are drawn from data from 60 UK online retail sites.The figures come after the CBI business organisation said UK retailers would face tough trading in the run-up to Christmas after sales volumes fell for the seventh month in a row in October.