Black Caribbean workers received the biggest pay rises on average during the pre-recession boom years, earning more per hour than their white peers by 2008, according to new research.

Researchers from the University of Essex say that although the gap between the hourly pay of white people and those from ethnic minorities as a whole more than doubled in the 15 years to 2008, there were marked differences between groups.

In an article published in the latest edition of the journal Work, Employment and Society, Essex University's Malcolm Brynin and Ayse Güveli analysed more than 650,000 results from the UK's large-scale quarterly Labour Force Survey.

This showed that in the four years beginning in 1993, pay per hour for whites averaged £6.90, 40p more than that earned by black Caribbeans, 30p more than British Indians and £2.20 more than Bangladeshis in the UK.

However, in the four years to 2008, the position was reversed with black Caribbeans' average hourly pay rising to £8.40 – more than whites, who earned £8.10 an hour. British Indians, Pakistanis and Bangladeshis all earned less and only British Chinese matched their Caribbean peers' hourly pay levels.

"It was a very surprising result," said Brynin, who lectures in sociology at Essex University. "But I think this is really about the success of black women in the public sector. In somewhere like nursing there is no doubt they succeeded and got well-paid, secure jobs."

The academic accepted that by many measures black people appear to be seriously disadvantaged in Britain – suffering high rates of incarceration and unemployment. But he said he was concerned "with what goes on in the labour market, not outside it".

Experts said "hard-won gains" by black people before the recession would disappear as cuts disproportionately affect ethnic minorities. Last year a quarter of a million public sector staff lost their jobs as the government's austerity measures started to bite.

Rob Berkeley, director of the Runnymede, a race equality thinktank, said that for "black Caribbean families the public sector is a source of stability and employment. If you see jobs going in the public sector then the impact will be particularly severe on black women. You will see their advance disappear."

Berkeley also pointed out that more than half of young black people were growing up in lone-parent households. "If levels of unemployment go up for black Caribbean women then there would be significant repercussions for the whole community."

The authors of the paper also warned against the idea that the data could be used to suggest that barriers or racism do not exist for non-whites.

In fact the gulf was growing. Brynin pointed out that in 1993 white people earned an average of 18p an hour more than non-whites, but by 2008 the gap had risen to 43p an hour.

The paper states that most of the gap between "whites and non-whites was caused because non-whites found it harder to get into well-paid professions and trades".

"The analysis shows not only that the ethnic pay gap varies considerably by ethnic minority but that it is in large measure the result of occupational segregation," the authors say.

Even where the two groups worked in the same profession or trade, there was a gap in pay – by 2008 whites were earning an average of 18p an hour more than non-whites doing the same type of work. This compared to 1993 when non-whites earned an average of 3p an hour more than whites in the same profession or trade.

Brynin said the overall gap had widened despite the fact that the proportion of people in most ethnic minorities groups working in managerial jobs was about the same as whites by 2008 – around 45%. This was probably because non-whites did not get "ahead in the job hierarchy".

"It is clear that on this basis most ethnic minorities earn consistently less than white people, if not always by much. One implication is that some minorities do not earn as much as their education would warrant."