Record producer Pete Waterman, who worked with Summer in the 1980s, said his abiding memory was of "a lovely person."
The singer teamed up with Stock Aitken Waterman in the late 1980s.
Whenever you were with her she made you feel so special. She had all the talent but she gave you all the credit. She was not a diva in any shape or form.
She was in the wilderness when we had the biggest record of our careers together.
They warned us against working with her because of the whole anti-gay thing that had happened.
But what a voice she had.
She used to warm up in the ladies toilet and everyone in our building would stop and it would come to a standstill to hear her warm up.
More top news
In her Brexit speech on Tuesday, the Prime Minister is set to urge the EU to forge a fair trade deal or risk commercial war.
B-Street Band want to remain respectful to Bruce Springsteen, who supported Hillary Clinton in the US Election.
Apollo 17 astronaut Gene Cernan died at the age 82 on Monday, Nasa has announced.