David Cameron insists his Government has "resolve, strength and grit" as he defended a string of enforced U-turns on tax measures.

The Prime Minister said it took courage for an administration to admit it was "ploughing into the brick wall" and change course on high-profile policies.

On Thursday, Chancellor George Osborne bowed to intense pressure to cap tax relief on charitable donations - his third Budget about-face in less than a week.

The switch came hot on the heels of fundamental changes to levies on pasties and caravans announced in March's financial package.

Since taking power in May 2010, the Tory/Liberal Democrat power-sharing coalition has made at least 21 prominent climbdowns - with critics putting the figure far higher.

Labour said the Budget had become an "embarrassing shambles".

But while he acknowledged the "difficulties" thrown up by the Budget, Mr Cameron sought to make a virtue of the Government's willingness to accept its mistakes.

"We've taken difficult decisions on the deficit which we've cut by a quarter in two years, difficult decisions on public sector pay, reforming public sector pensions, standing up to public sector strikes," he told BBC1's Andrew Marr Show.

"Nobody thinks this Government lacks resolve, strength and grit.

"It has all of those things and it also has the courage to say 'Look, if we've got something wrong, let's change it; let's not keep ploughing into the brick wall'."