Chancellor Philip Hammond has lost a second special adviser in a matter of months, with the Investment Association recruiting one of his chief lieutenants.
After almost a year in the Treasury alongside Hammond, Graham Hook has joined the trade body to serve as interim head of government affairs.
Hook was a long-term resident of Whitehall, having previously served with Hammond in the Foreign Office, the Ministry of Defence and the Department of Transport over the past six and a half years.
He quit as an advisor in May, but is only expected to serve a short-term contract at the trade body before leaving later this year.
An Investment Association spokeswoman said: “We are delighted to welcome Graham to the IA as our interim head of government affairs.
"His recent experience across government will be invaluable as the IA continues to build up its corporate affairs function in the coming months. He will be with us until the autumn.”
It marks the second notable departure from Hammond's team, with communications director Hayden Allan quitting to move into the private sector in April.
Speculation about Hammond's own future after this week's election is also rife.
The chancellor's approach has put him at the centre of briefing wars in parliament, with Cabinet colleagues last year bemoaning a habit of "thinking like an accountant seeing the risk of everything". Earlier this year the Treasury was also forced into a humiliating u-turn over plans to hike national insurance contributions for self-employed workers just days after Hammond announced them in the Budget.
Prime Minister Theresa May has repeatedly refused to say whether he will remain at the Exchequer.