Homeowners in the commuter towns of the southeast are cashing in and moving on.
Rightmove said that it had recorded its biggest ever annual jump in seller numbers in the region, fuelled by strong demand and the stamp duty holiday.
Harlow in Essex, for instance, has seen a 121% increase in newly marketed properties, while demand has soared 90%.
Estate agents said that sellers were responding to inquiries from buyers who were looking to trade-in places in the city for more space outside London.
Rightmove said that demand for new homes had risen by 61% nationally, but that commuter towns in the southeast had registered growth of 74%.