Image copyright Getty Images Image caption Mr Murphy insisted he was leader of Scottish Labour, not Ms Abbott

Scottish Labour leader Jim Murphy has rejected claims he is trying to "buy" Scottish votes with money "expropriated" from London.

Mr Murphy has pledged that a UK-wide "mansion tax" would allow a future Labour government to create 1,000 new nursing posts in Scotland.

He said most of the money raised would come from London and the south east.

Labour MP Diane Abbott accused him of "unscrupulous" behaviour, but Mr Murphy insisted his plan was "sensible".

Mr Murphy compared the plan to spend money levied on English homes on Scottish nurses with the way the oil wealth from the North Sea was shared around the UK.

"It's part of pooling and sharing your resources across these islands, it's pretty sensible," he told BBC Radio 4's World at One programme, and pointed out the property tax was Labour Party policy.

'Tax' on Londoners

Labour has pledged to impose what it calls a "mansion tax" - a levy on homes worth more than £2m across the UK to fund the NHS - if leader Ed Miliband wins the general election.

In his first major policy announcement, Mr Murphy said he would use Scotland's share of the money, allocated under the Barnett formula, to pay for extra nursing staff, if Labour wins May's UK General Election and then the Scottish Labour Party wins the Holyrood election in 2016.

But Ms Abbott, the Labour MP for Hackney who hopes to run for London mayor, told the World at One she was very surprised that Mr Murphy was "making these boasts".

Analysis by James Cook, Scotland Correspondent

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With phrases like "fiscally vindictive" and "highly unscrupulous" being hurled around, it's clear that a political row is playing out which is as bitter as it is old.

It is being contested on familiar turf: does the rest of the UK, and particularly wealthy London, subsidise Scotland?

The front pages of the London editions of The Times and The Daily Telegraph both concentrate on a "pledge" from the Scottish Labour leader Jim Murphy, made as he kicked off his campaign for the general election.

"Mansion tax to fund nursing in Scotland" is The Times' headline. "Labour tax on 'wealthy English' to fund nurses in Scotland" is the Telegraph's take.

Believe it or not, those headlines will suit Mr Murphy. The new leader of the Scottish Labour Party has a tough task.

Read more from James

"Jim Murphy is saying that he's going to be recruiting nurses from day one on the basis of this mansion tax. You can't recruit people on the basis that money that hasn't even been raised yet," she said.

She added: "Jim Murphy is jumping the gun in a highly unscrupulous way."

While supporting the mansion tax "in principle", Ms Abbott said a lot of discussion was needed as to how to implement it fairly, warning it amounted to a "tax on Londoners".

She said the policy would affect people who bought homes many years ago which have since increased substantially in value, while the wealthy would try to "evade" the tax.

"That's all got to be thought through - Jim Murphy isn't waiting for that. He just thinks he can buy Scottish votes with money expropriated from London," she said.

'Cash cow'

Mr Murphy - who Ms Abbott mistakenly called 'John' at the start of the interview - hit back by saying he did not have to consult Ms Abbott or clear things with Labour leader Ed Miliband over what he does in the Scottish Labour Party.

"When it comes to issues that are devolved - so health and education in Scotland - I am in charge. I am the leader of the Scottish Labour Party."

Reserved issued such as foreign affairs and welfare, he added , were the responsibility of the Labour leader, who he said he looked forward to campaigning alongside for a Labour victory at the general election.

Ms Abbott, he suggested, should get behind Labour Policy "rather than either forgetting my name or attacking my approach to what I do in Scotland".

Image copyright Getty Images Image caption Jim Murphy MP became the new leader of the Scottish Labour Party in December last year

Conservative Party chairman Grant Shapps said Mr Murphy's comments showed "once again that Ed Miliband simply does not command the respect of his party".

A Labour spokesman said the "overwhelming majority" of money raised would be spent in England, "but as with any UK-wide tax, Scotland will receive a share of the proceeds under the Barnett formula".

"It is up to the Scottish Government how to spend this revenue," they added.

Scottish National Party MP Angus Robertson said: "Fickle attempts to win back trust by playing an arbitrary numbers game with nursing staff and proposing oil funds that Labour should have supported decades ago are wide off the mark - and people will see straight through them."

The policy announcement, made by Mr Murphy on Monday, has also faced criticism from some other London-based politicians.

Mayor of London, Boris Johnson, described the plan as "fiscally vindictive" to the south east of England and amounted to trying to "bribe the Scots to vote Labour", while Labour's Dame Tessa Jowell said London should not be treated as a "cash cow".