The plan, currently under consultation, aims to target either high earners, large repayments, or both, but Centre Forum says most early payments aren't made by high earners.
And doctors complain that Oxford, much more than other insurers, accuses them of years of overbilling, based on minimal evidence, and demands large repayments.
Our results show that individuals contribute more when large repayments are feasible.
Excessive penalties lead to negative-sum games, in which the debtor cannot recover and creditors do not benefit from the larger repayment capacity that recovery would entail.
Last year the public sector ran a surplus of £18 billion ($27 billion), £6 billion more than forecast in the budget in March, and the largest repayment of debt since the second world war.The record surplus reflects the fact that public spending undershot last year.
If you don't have a large early repayment charge on your mortgage and you have some equity in your home and your circumstances haven't changed, you'll almost certainly be better off remortgaging or taking out a further advance from the same lender," states the Money Advice Service website.
Eurozone finance ministers are now racing to find a way to provide Athens with funding in the interim, especially so that it can meet a large debt repayment to the European Central Bank next Monday.
South London faces the largest annual repayment in 2012-13.
Argentina faces large debt repayments to the Fund in 2002 and 2003.
Western sanctions on Moscow for its annexation of the Ukrainian region of Crimea and support for pro-Russia rebels fighting the Kiev government have shut out Russian companies from western capital markets, forcing large debt repayments and prompting fears of a slow-motion credit crunch.
