2.148 VED: classic vehicle exemption – The Government will extend the cut off date
from which classic vehicles are exempt from VED by one year. From 1 April 2014 a vehicle
manufactured before 1 January 1974 will be exempt from paying VED. (Finance Bill 2014)
Can't see any mention of a rolling exemption anywhere, though there is press speculation that it may happen
It will be offset by an increase in VED for cars younger than that though that somehow didn't seem to be in his speech either

2.146 VED rates and bands – From 1 April 2013 VED rates will increase in line with RPI, apart
from VED rates for heavy goods vehicles (HGVs) which will be frozen in 2013-14. (Finance Bill
2013). The Government has no plans to make significant reforms to the structure of VED for
cars and vans in this Parliament. (58)