I picked this leak up through loose twitter chat and then secured a copy of the relevant document which seems genuine. Have a look and make up your own mind. I've uploaded the full document here. The Ministerial briefing notes are most illuminating so I have copied them below.
22 April 2009
NOT FOR WIDER CIRCULATION.
As you know, last year HMRC consulted on future changes to the VAT registration thresholds.
Plenty of comments were received as regards a number of options and on the desirability of change.
Respondents generally supported the idea of a significant increase in the VAT registration threshold.
Ignoring the strength of feeling is not a viable option in the current economic environment.
Looking at EU law and the impact of the recent movements in the exchange rate between sterling and the euro we are in a unique position to increase the VAT registration threshold to the highest permitted figure of 100,000 euros.
Following last year’s consultation the Treasury has sought and received confirmation that the UK’s VAT registration limit can be increased by reference to the [current] sterling/euro exchange rate. 100,000 euros = £100,000.
Obviously we hope that the exchange rate will improve but Treasury have advised that the VAT registration limit would not need to be reduced if this occurs.
Otherwise the subsequent change would have a serious negative PR impact for the Chancellor as did the reduction in the rate from 17.5% to 15% announced in the PBR.
Lastly we recommend that the Chancellor express his specific thanks to the Chairman of the Tax Advice Network for the insightful commentaries on his TaxBuzz blog www.taxbuzz.co.uk