A committee of MPs is to investigate how to ensure Parliament's Clock Tower - better known as Big Ben - can be prevented from tilting further, after surveyors found it was leaning.
The Palace of Westminster, constructed during in the 19th Century, is also suffering from cracking.
The House of Commons Commission meets on Monday to discuss the problems.
But Professor John Burland of Imperial College said the lean should not be a big worry for at least "10,000 years".
During their meeting the MPs are expected to discuss a proposal to sell the Palace of Westminster and move into new offices, although this is thought to be highly unlikely to happen.
They will also look into the option of moving out temporarily while renovation work is carried out.
'Long time ago'
The Clock Tower, housing the bell which is called Big Ben, was completed in 1859.
Since then a five-storey car park and the Jubilee underground line have been constructed.
Imperial College London Prof Burland, a construction expert who oversaw the building of the car park, told BBC Radio 4's Today programme the lean had "been there for years. When I first started work on the car park it was obvious that it was leaning.
"We made measurements on it. It was leaning at one in 250 to the vertical, which is just about visible. That's the break point between looking vertical and looking like a slight lean.
"We've known about it for years and it was probably developed at a very early stage because there's no cracking in the cladding and we think it probably leant while they were building it and before they put the cladding on.
"That was a long time ago and buildings do lean a little bit."
Dally Fora Pois talks to tourists about the future of Big Ben: published October 2011
It is not the first time there have been problems with Big Ben, which stands at 96m (315ft) tall.
In 1976 pendulum weights fell down a shaft and the clock mechanism exploded, putting it out of action for almost nine months.
Prof Burland said the cracks in the Palace of Westminster had been there for years.
He added: "There's no such thing as an old building that isn't cracked. In fact they're beneficial because the building moves thermally more than is caused by the Jubilee Line and the movements concentrated around the cracks and, if they didn't, there'd be cracking elsewhere.
"For the time being, Adobe have set up an automated correction (from ver PS CS5.0 on) that every time Big Ben is snapped, Photoshop (including Elements from V5) will auto correct the lean so that it cannot be spotted by the naked eye ", he added "This way we can defer building work until the economy can better stand it"
the saving is expected to be in excess of £1 billion ($1.5 billion)
any photographers not using PS should tilt the camera approximately 1 deg clockwise (when shooting from the south) to compensate for the lean.
Addendum - STOP PRESS, we have just found out that Big Ben is to be given digital readout in time for New Year celebrations 2020. the govenrment are putting out to tender for sponsorship of the change and the original four clock faces are to be auctioned and the proceeds to go to Greenwich schools.
Omega have registerd interest and have already submitted a bid.