Big office estate agents in the City of London enjoyed a bumper end to 2018, as companies rushed to lock in new premises despite the looming threat of Brexit.

Christian Ulbrich, global chief executive of JLL, the property agency, told Financial News at the World Economic Forum in Davos, that his company had leased more space in the Square Mile during the final three months of 2018 than in any other quarter on record.

Leasing...