The contractors responsible for this are working for the London Borough of Waltham Forest. East Avenue E17.
Department for Transport
LTN 1/04 - Policy, Planning and Design for Walking and Cycling
4.14 Temporary measures for pedestrians and cyclists
Cyclists and pedestrians at road works
4.14.1 It is important to ensure that the safety and convenience of pedestrians and cyclists is not compromised by road works
As on Markhouse Road E17:
(Below) Where better to put a temporary traffic sign than the cycle lane? Hoe Street/Queens Road. And note the collapsed fencing in the foreground. Still, it's good to know that there's at least one driver in London who respects an ASL.
Where better to put a sign for drivers than across the pavement? Gosport Road E17.