Blair has been drafted in to replace group communications MD Locksley Ryan, who resigned last week after just nine months in the job (PRWeek, 9 July).
Blair has started on a three-day-a-week secondment from London Communications Agency, the corporate comms firm he joined last November from FH.
He takes charge of around 80 comms staff and expects to remain in the post until at least September.
A decision has yet to be made on when a recruitment process will begin for Ryan’s full-time successor. Ryan quit after a breakdown of relations with transport commissioner Bob Kiley.