You could ask HM Revenue & Customs (HMRC) to collect your tax liability gradually from your employment income by adjusting your tax code. In order to do this, make sure that box 2 on page 5 of the tax return is blank before you file your return and the return is filed by 30 December 2011.
Please note, anyone can request to have their 2010/11 tax liability settled like this, provided their tax liability is under £2,000 and they submit their return by 30 December 2011 (from next year, the limit will be increased to £3,000).
Alternatively, there may be scope to negotiate a Time to Pay Arrangement with HMRC, which is effectively a payment plan.
If you would like to discuss your difficulties with settling your tax liability further, please do not hesitate to contact your local TaxAssist Accountant.