Venue association the Westminster Collection has announced that 28 Portland House is the latest venue to become a member.
The London venue is the collection's 50th member and according to the Westminster Collection, it has achieved a 100 per cent growth rate this year and expects further expansion in 2011.
The Westminster Collection chief executive Rene Dee said: "I am very pleased to welcome 28 Portland Place into our growing and loyal membership. Being our 50th member, a milestone in itself, it represents all of the qualities and attributes that have guided us in our development."
He added that the achievement is just the start of what the association hopes will be a productive and exciting year in 2011.
The collection includes 76 Portland Place, Central Hall Westminster, the Caledonian Club, the Chesterfield Mayfair Hotel, the Private Rooms at 51 Buckingham Gate and Number 45 Millbank.
Back in 2009, the organisation also announced that the Society of London Theatre had joined.