document: Andrew George, who was re-elected Liberal Democrat MP for St Ives in May, is one of four MPs to have tabled an amendment to the finance bill.
  It follows the government's budget announcement that from 4 January VAT will rise from 17.5% to 20%.
  Mr George wants the government to assess the impact of such a rise on businesses, charities and households.
  The other three Liberal Democrat MPs who have put their name to the amendment are Bob Russell who represents Colchester in Essex, Mark Williams who is MP for the Welsh region of Ceredigion and mid-Wales and MP Roger Williams, whose constituency is Brecon and Radnorshire.
  Mr George said: "I am not trying to trigger nuclear war and break up the coalition, it's perfectly normal for two parties to have different approaches and values.
  "I just want to express my unhappiness with the move and have an open debate."
  Mr George also said he hoped a government minister would respond to the amendment on Monday and added he would continue to look for opportunities to press his case.
summary: An MP from Cornwall is calling for an investigation into the impact of increasing VAT to 20%.