Urban Realm reports 'Projected Aberdeen bypass costs almost double to £653m'

Anyone good at this sort of maths?  

'...Plans to construct the Aberdeen bypass, recently approved by the Supreme Court, has hit a fresh stumbling block with news that the projected bill for the 28 mile route has nearly doubled from £347m in 2008 to £653m today.

Transport Minister Keith Brown has blamed a succession of delays incurred by a tortuous legal process, brought about by repeated legal challenges mounted by a campaign group fighting against the plans, has led to the ‘substantial increase’.

Outlining the basis for the price hike Brown told MSP's it reflected "scope changes, the inclusion of standard risk costs and rebasing to 2012 prices", with inflation alone contributing £230m to the increase.'

How can 4 years inflation add up to £230m?

original item here