International public law set 10-11 Gray's Inn Square has poached a senior tenant and taken on new premises.
Michael Murphy, an immigration and criminal practitioner, has joined from 8 King's Bench Walk.
Senior clerk Richard Loasby says the set is boosting its environmental crime and immigration teams to meet a booming demand.
Murphy's addition brings the immigration team up to nine practitioners.
The new premises, beneath their building, will give the chambers - which has 32 barristers - the capacity to reach 50 tenants and the set is already in negotiations to recruit five more.
The set, led by one of the youngest heads of chambers at the bar, Mark Muller, 34, launched an ambitious expansion drive last year.
It followed Bar Council research that showed chambers of up to 30 tenants were most at risk of decline.
It successfully recruited nine new tenants to escape the danger threshold and is now run as a limited company with five directors and chairman Muller, who is vice-chairman of the bar's human rights committee.