The Government has endorsed a Liberal Democrat-sponsored Bill to write into law a minimum 0.7% spending commitment on international aid, despite objections from Tory backbenchers.

Des Swayne, a Conservative minister at the Department for International Development (DFID), confirmed Government support for Michael Moore's private member's bill during a second reading debate in the Commons.

He told MPs the pledge had been enshrined in the Coalition Agreement at the start of the Parliament and had also featured in both the Conservative and Liberal Democrat manifestos.

Tory MPs have argued aid spending should not be going up while other departments - particularly defence - face cuts and questioned the wisdom of putting the DFID budget into law while other departments have their spending determined in the normal way.

The Bill requires no additional spending as the target was hit at the 2013 Budget. It will mean spending of about £11 billion in 2015/16.

Mr Swayne told MPs: "I feel bound by commitments that I have made and I made a commitment at the last general election to 0.7%."

The Tory minister deflected criticism from some of his own backbenchers that "charity should begin at home".

Mr Swayne insisted international aid is not charity, it is taxpayers' money spent in the national interest. Labour also backs the International Development (Official Development Assistance Target) Bill, which will be voted on later, with shadow DFID secretary Jim Murphy and former prime minister Gordon Brown both breaking off from the independence referendum campaign to back the plans.

Mr Murphy said: "British aid works. The support we give changes lives."

But Tory James Gray (North Wiltshire) spoke saying: "No one in this House doubts the value of aid. Domestic spending of any kind is not written into law, why should this be the only thing written in law?"