Shortfall on tax due

If someone had already deferred tax for a period of years and now that tax is due this year 2009.If you are short on tax due and have no way of getting a loan to cover the shortfall what options are there.Shortfall is around 20K.Is it worth speaking to Mabs or something similar.Can the revenue make you sell your house.Can you defer tax for a further period of time?
All advice welcome

Revenue may enter installement arragement. But ibnterest rate will be high.

Unlikely in the extreme revenue can force you to sell your home.