John McDonnell is today putting in effort to explain his u-turn on George Osborne’s fiscal charter, which will be voted on by MPs tonight. As well as articles by the Shadow Chancellor in the Independent and Mirror today, LabourList has also seen a media briefing circulated among Labour MPs, which intends to clear up confusion about the change in stance.

Having been doorstepped by the BBC this morning, McDonnell admitted that the move may have puzzled members of the PLP, but insisted that “today we’ll clarify everything”.

The briefing for MPs does not make reference to the previous position on this evening’s vote, where Labour will now be voting against, but instead draws attention to how this fiscal charter “is different to the one Labour voted for in January”. Where the previous charter supported year on year reductions to the deficit (which is Labour policy anyway), the briefing argues that Osborne’s new charter “binds the hands of a government to austerity, regardless of what’s right for Britain, it would mean that we couldn’t borrow for capital investment”.

Labour’s new opposition to the bill was announced by McDonnell in a letter to Labour MPs on Monday. You can read the full letter here.

McDonnell has two op-eds in the morning’s papers, as he seeks to clarify the new position. In the Daily Mirror, he describes the vote as a “Tory Charter trick” and says that “Labour won’t play these silly Westminster games anymore”.

He says that visiting families in Redcar last week, where over 2,000 people are losing their jobs in the steelworks closure, convinced him of the need to underline Labour’s “position as an anti-austerity party by voting against the Charter”.

In The Independent, McDonnell cited the “gathering economic storm clouds” as a reason for his change of heart. He writes:

“Initially I thought it best to treat the vote with the contempt it deserved, vote for the Charter, avoid claims of deficit denial and move on. The gathering economic storm clouds and the implications of the Charter in terms of cuts to services, tax credits cuts for millions of families, and constraining investment for the future have become much clearer and have persuaded me Labour should not be associated with it at all.”

Osborne has today called on “all moderate, progressive Labour MPs to defy their leadership and join with us to vote for economic sanity”. While some Labour MPs were unhappy with the way in which the u-turn came about, it is unlikely there will be much of a rebellion – although some backbenchers may choose to abstain.