The Sailor's Rest on St Peter's Street was threatened with demolition in 1970
The body which aims to preserve the character of Suffolk's county town is celebrating its 50th anniversary.
The Ipswich Society was formed in 1960 at a time when the town was undergoing rapid redevelopment.
More recently its been liaising with planners over the waterfront and putting up blue plaques.
"We steer a careful balance between preserving the best of the old whilst ensuring economic viability," said John Norman, vice chairman.
The Ipswich Society has around 1,200 members, but it started out with just a handful of enthusiasts.
"The government after the [1939-45] war decided to do something about our built environment," said Jack Chapman, chairman of the Ipswich Society.
"There was a lot of activity in looking at town centres, the bombing damage and trying to re-plan them.
The Willis building (early 1970s) meets with the Ipswich Society's approval
"Once a national civic trust was set up a lot of towns set up their own versions and the Ipswich Society was one of the first to get off the ground.
"We're not a preservation society. We don't believe in preserving everything in aspic. Ipswich is a living town and it's going to alter.
"We're keen to scrutinise what's happening, shout about it when it's good and bad.
"We'll win some and lose some, but either way we're passionately involved in how the town develops.
"I took up my job in Ipswich in 1969. The Greyfriars complex shocked me.
"Two other places made a lasting impression - one, the red-brick cinema cheek-by-jowl with the Ancient House, the town's finest building [on Buttermarket] and the other, the state of the dock where abandoned warehouses were sliding slowly into the water.
"I'm glad to say that the cinema is no more and the waterfront has a vastly improved image."
The society says it has a valuable contribution to make to planning decisions and is actively involved in the process.
"They also have an important role to play in safeguarding the town's heritage," said Steve Miller, development control manager at Ipswich Borough Council.
"Ipswich Society are a valuable resource who, with their input at various levels to the development process in the Borough, have aided in the raising of design levels and the importance of good design generally.
"Their contributions are valued and taken account of. I don't think we have ever 'fallen out' with them but of course there are differences of professional opinion.
"I welcome their future involvement and input into the future of the Borough."
The atrium at Suffolk New College which opened in 2009
The 50th year events start on 23 April with the AGM in one of the society's approved buildings - the atrium at Suffolk New College.
The guest will be The Guardian's architectural correspondent Jonathan Glancey, who lives in Suffolk.
A walker's booklet is being produced which will list the society's favourite buildings such as the black glass clad Willis building, Arlington's Brasserie on Museum Street and Isaac's pub on the waterfront.
But it's not just old buildings that have been saved. The Spinney, which is a modern wooden house on Westerfield Road, was threatened with demolition and redevelopment as a care home.
The society campaigned alongside some local residents to have it listed.
The society's also going to help pave an area for seating outside Christchurch Mansion.
A trio of blue plaques
The anniversary year also sees the addition of three Ipswich Society blue plaques to buildings.
Nathaniel Bacon's blue plaque is on St Margaret's Green
The artist Leonard Squirrel (1893-1979) is getting honoured at 82, Spring Road.
Philanthropist and MP Felix Thornley Cobbold (1841-1909) is getting a plaque which will go on the Reg Driver Centre in Christchurch Park and rebellion leader John Harbottle (d.1578) will have his on Northgate Street.
"This year I'm focussing on the celebrations," said Tony Marsden, the society's plaques man. "They've taken up quite a bit of time in the past four years.
"It takes a lot of work getting the various permissions, but it's good fun.
"So, I'm having a bit of a rest until autumn, but there's a sergeant with a VC I'm working on."
For more details about activities and membership visit
The Ipswich Society