The coronavirus pandemic has increased recognition of the benefits that immigrants bring to UK society and the country's economy.
The sight of migrants putting themselves at risk in frontline health services led to a softening of attitudes, according to the British Foreign Policy Group's annual survey.
But the poll showed a growing enmity towards China over its perceived invasive technology, human rights record and attitude towards its Muslim Uighur population and Hong Kong.
Immigration was one of the key issues influencing people in Britain who voted in the 2016 referendum to leave the EU, in part blaming migrants for taking their jobs.
However, attitudes have changed during the coronavirus outbreak, with more people recognising the benefits immigration brings.
With Brexit now concluded, Britain is apparently able to control migrant numbers, which “allows otherwise concerned and insecure citizens to look more favourably towards migrants”, the report said.
Half of those polled agreed that the hard work and talents of immigrants strengthened Britain, with 50 per cent saying immigration had a positive economic effect. Less than half of the participants believed that accepting migrants from a wide range of nations made Britain stronger.
“This trend is significant and could signal a pathway for some of the heat to come out of the public debate on immigration over the coming years,” the report said. “When we consider the evolution of public opinion during the pandemic, we can see that the majority of the movement has been in the more favourable direction towards immigration.”
There was a significant increase in the number of people who thought immigrants strengthened the country, with an increase of five percentage points on last year's survey.
However, a large number "ultimately believe that the costs of immigration outweigh their benefits", which was a "deeply polarising and potentially combustible issue".
Those with a positive attitude to migrant contributions tended to be university graduates, under 35, from London and from ethnic groups. In contrast, those less supportive were typically over 55, without university education, from Wales or east England and in less well-paid jobs.
“Britons from lower socio-economic backgrounds and school leavers are significantly more likely to believe that immigrants take jobs from other Britons, compared to more economically secure Britons and graduates,” the report said.
A record 8,400 asylum seekers attempted to cross the English Channel last year. "There is a sense that it has the potential to become a volatile issue with political consequences, as it has done in many other western nations over the past decade," the report said.
It found that many people in Britain view China as a menace and are against creating further economic ties. China was regarded as a critical threat by 41 per cent of respondents, up from 30 per cent last year.
British attitudes to America improved with the election of President Joe Biden. Almost half said they would trust the US to act responsibly, a significant increase on the 28 per cent under Donald Trump's leadership.
