■ Failure to meet demand could not only inhibit the growth prospects of local businesses (as rents inevitably rise), but also could make it harder for the city to attract companies looking for a home in one of Britain's regional centres.

■ As permitted development rights are extended and made permanent, our research shows that there is a clear value advantage in converting commercial space into residential in three of the nine areas we analysed.

■ The city will need to expand to meet demand. We track the development hotspots for the next decade.