Gabrielle Giffords, the Arizona politician who was shot in the head in January, said she had been "deeply disappointed" by the party political wrangling that brought the US to the brink of an unprecedented default, after her return to Congress for a vote on the debt-ceiling bill.

To rapturous applause from both Republicans and Democrats, the convalescent congresswoman appeared in the House of Representatives with minutes left before the end of the vote, walking unsteadily and mouthing "thank you" to those who had leapt to their feet to welcome her back, including the Vice-President Joe Biden and the Tea Party favourite Michele Bachmann.

Such a show of unity had been rare in the weeks leading to the vote, a fact Giffords, a Democrat, observed in a statement released afterwards.

"I have closely followed the debate over our debt ceiling and have been deeply disappointed at what's going on in Washington. I strongly believe that crossing the aisle for the good of the American people is more important than party politics," she said.

Giffords, who is still undergoing outpatient therapy, added: "I had to be here for this vote. I could not take the chance that my absence could crash our economy."

Her vote in favour of the bill was one of 269 that sent it through the House with a hefty majority. Hers was without doubt the most enthusiastically greeted.