I take issue with the concept of "mandate"
Under our appalling FPTP electoral system many voters, living in "safe seats" are totally disenfranchised. Others, many others, vote tactically against the candidate they hate the most.
I've just spoken to two friends, both living in Scotland, about the recent general election. Both voted tactically. They both believe strongly that Scotland should remain in the UK and that the UK should remain in the EU.
One friend, in her seventies, told me she had voted Tory for the first time in her life because she hates Nicola Sturgeon and her separatist ambition. NS wants to destroy the UK and , for my left-of-centre friend, that was the most important issue and so she held her nose and voted Tory because in her constituency, the Tory candidate was the only one who could defeat the SNP, and she was pleased to see the Tory candidate elected. She is opposed to almost everything in the Tory manifesto, but for her, it was more important to keep Scotland in the UK.
The other friend, a life-long Liberal, who would like more than anything to elect a LibDem MP, actually voted Labour for the same reason, to try to stop the SNP. Unfortunately he still ended up with an SNP MP.
Neither of these people endorses brexit, let alone the hard brexit which apparently both Tory aim for now. Yet the brexiteers have the cheek to say that since over 80% of those who voted voted Tory or Labour, all these people have given them a "mandate" for hard brexit. RUBBISH!!!