Almost a third of new houses completed last year were sold off-plan as buyers sought extra room during lockdown.
Research by Hamptons found that sales of houses prior to the completion of building work had risen to record levels, from 29% to 30%.
Off-plan sales of flats, however, had declined from 58% to 50%.
The slump in flat sales meant that the total proportion of homes sold off-plan actually fell to 33% from 35%.