What was in your opinion the most underrated European computer pre 1990s

The whitechapel. A graphics workstation with mouse before it was cool.

The early Olivetti designs were out of this world. Very stylish.

The ICL designs were cool, but an awful lot of things at ICL are really imports so the icl perq was really a 3 rivers bitslice machine afaik. But very very cool (I did animated icons on one using a bitmap editor called "cedra")

Probably the Acorn Archimedes systems which seemed to always be disregarded in favour of the Amiga and Atari ST.

The Sinclair QL didn't do very well either but I don't know if it deserved it or not. ICL released a version called the One Per Desk with an integrated phone handset.

Sinclair Spectrum ZX80 - sold 5 million units in the 1980's and legitimately brought home computer / home gaming to millions to people in the UK for first time.