Scotland Yard says it is "too early to speculate" on Russian reports that the attack could be a gangland hit linked to a murder attempt on another banker, Alexander Antonov, in Moscow.
The force's Trident command - which investigates gang shootings - is understood to have liaised with overseas counterparts in the hunt for the gunman behind the attack on Tuesday evening.
More top news
A 350,000 ton landslip in the Harbury area between Leamington Spa and Banbury yesterday is affecting both train services.
It is freezing cold again today in the cutting north-north-west winds. Northern Scotland can expect to see some snow.
Arsenal brushed aside Aston Villa 5-0 to move within a point of Man United in the race to qualify for next season's Champions League