Although not all agreed with his politics and some of the work of his former firm Bell Pottinger, Bell paid a pivotal role in shaping the modern communications industry.
Lord Chadlington, a close friend who introduced Lord Bell when he was inducted in the PRWeek UK Hall of Fame in 2016, said Bell was the first person to understand how integrated communications works.
"Advertising, public relations, interpreting research, sales promotion – he excelled at them all," Chadlington said.
"Tim had - like all of us - his failings. Sadly, some of these were all too public. But nobody - absolutely nobody - has done more to make PR a respectable profession and the aspiration of a generation of young graduates.
"Whether we are his friends, his work colleagues or his clients, we owe him an enormous debt of gratitude."
The communications agency that Bell founded with Piers Pottinger was one of the UK's largest during its peak, and also one of the most controversial. The agency was expelled from the PRCA in 2017 for its work for the Gupta brothers in South Africa, a scandal that tarnished Bell's reputation towards the end of his career.
Despite this, PRCA director general Francis Ingham said that of all who can be said to have made the modern PR and communications industry, "Bell stood preeminent, an undisputed giant who proved the power of communication".
He added: "Nobody can question he was controversial, and indeed he delighted in being so. But nobody can question his greatness either."
Michael Moszynski, the founder and chief executive of London Advertising who worked with Bell had on some "esoteric clients, such as the president of Congo-Brazzaville", reflected on Bell’s time in the ad industry.
"His first role in the ad industry was as the media man in the fledgling Saatchi & Saatchi in the early 1970s, where soon the brothers’ dependency on his ability as an all-round fixer/managing director resulted in him earning the sobriquet ‘the third Saatchi’," Moszynski said.
Cordelia Meacher, the founder of FieldHouse Associates, said: "While undeniably controversial sometimes, Tim was such a great man. He was very supportive and kind to me (and many others I gather), and I'll never forget that."
Others from the PR and media industries paid tribute to Lord Bell on social media.
"Lord Bell was a divisive figure in Public Relations, one who promoted the profession to business and government, even if the way he did things was not met with universal approval. We are nonetheless saddened by his passing." Comment by CIPR— CIPR (@CIPR_UK) August 26, 2019
RIP Tim Bell, a giant of the generation that made the modern British #publicrelations industry.— Tony Langham (@TonyLangham) August 26, 2019
Respected by rivals for his ability to make the complex seem simple, at Board level, in a way that no one else could. https://t.co/9OqILiLoq8
Sad news today. Tim Bell was a real leader and a truly remarkable man. Working with him from 1990-2003 taught me so much. An unforgettable man, RIP.— Shimon Cohen (@scohen_shimon) August 26, 2019
I am very sad about the death of Tim Bell. He had too few scruples about who he would represent. But he was the best company, always honest with me, enormous fun. He was a pirate of the old school. Almost none left. And the world is poorer for their passing— Robert Peston (@Peston) August 26, 2019
Not my politics. Not sure I agreed with his choice of clients. Nevertheless, he did blaze a trail for the likes of Campbell and Cummings— Mark Borkowski (@MarkBorkowski) August 26, 2019
I once spoke after him at a conference where he arrived direct from a stag night and told the same jokes had the night before. Needless to say no one remembered what I said about evaluation.— Richard Houghton (@agencydoctor) August 26, 2019