Triple accreditation is an accreditation awarded to 57 business schools 3 largest business school accreditation association. They are

The Association to Advance Collegiate Schools of Business (AACSB)
The Association of MBAs (AMBA)
European Quality Improvement System (EQUIS)

I am providing you with the list of triple accreditation schools in UK for your reference. Go through it.

Cranfield School of Management, Bedfordshire
London Business School, London
Ashridge Business School, Berkhamsted
Hull University Business School, Hull
Cass Business School, City University London, London
Warwick Business School, University of Warwick, Coventry
Strathclyde Business School, University of Strathclyde, Glasgow
Manchester Business School, University of Manchester, Manchester
Durham Business School, Durham University, Durham
University of Sheffield Management School, University of Sheffield, Sheffield
Henley Business School, Henley-on-Thames and Reading
Aston Business School, Aston University, Birmingham
Open University Business School
Lancaster University Management School, Lancaster
ESCP Europe, London