According to a story in the FT, George Osborne wanted to release the British Geological Survey report on shale gas in time for the budget.
Apparently Ed Davey decided to ask the BGS to rework the numbers.
...the energy department is understood to have asked it to redo its calculations, a process that is taking several months. A final report is still a few weeks away and could see a downward revision to the estimates.
Now why would Ed Davey want the shale gas estimates to be lowered?