Four years ago, Professor Anthony King criticised the BBC at a UK level for ignoring political developments in Wales and Scotland.
But in a Royal Television Society Wales lecture he said there had been "an enormous change" in how the BBC now reported on devolved nations.
However, he said more could be done to compare policies across the UK.
Delivering his speech at the RTS Wales annual lecture, Prof King said he believed that while mistakes still happen - it was much less common.
"I think there has been enormous change," he said.
"I live in the east of England, I look out for the failure of the BBC to mention what is going on in Wales, what's going on in Scotland and to give the impression that everything that affects England affects everybody else in the UK.
"They make many fewer mistakes than they used to."
His comments are in stark contrast to a review he carried out for the BBC Trust in 2008.
In that report, the professor of government at Essex University, stated that the BBC was "not reporting the new UK with the range, clarity and richness that might reasonably be expected".
Speaking in Cardiff on Thursday evening, he said the task now at hand for the BBC was to show more clearly just how devolution impacted on everyday policies across the UK.
"If the NHS is run differently in Wales than the way it is run in England, I want to know why it is run differently, how it is run differently, and what difference that makes to the people of Wales," he said.
"I think it is still the case that the English don't quite take on board the reality of devolution.
"They know about it as a concept, but they don't really know what its meaning is on the ground, and they don't know that things are going on very differently in different parts of the country, with very different outcomes."
The BBC's coverage of Welsh devolution has significantly improved on UK-wide programmes, says a leading academic.