After retiring last week after 16 years as Watford’s mayor, making me the longest-serving directly elected woman mayor in England, I feel more strongly than ever that mayors are the key to reviving local democracy. For me, councils have missed a trick in not adopting the mayoral system more widely. Since mayors often represent an electorate much larger than that of any MP, their mandate makes it harder for ministers to treat them with the mixture of condescension and contempt usually reserved for local government.

At one level mayors have no more direct power than council leaders. But they have more soft power. You are the mayor of a place, not just the leader of a council. The mandate from the public gives you a licence to interfere in things that are not your direct responsibility. I used this in various ways: supporting efforts to bring Warner Studios (now the Harry Potter Experience) to the Watford area, getting town centre businesses to agree to a business improvement district, and influencing policing policy in our town centre in a more liberal direction.

Sometimes hard power helps too. I like to think that my persuasive powers made a difference in keeping hospital A&E services in Watford when they were under threat; but being able to make council-owned land available to the hospital for improved access and facilities certainly did. I was not in charge of the local NHS, but people expect their mayor to support the hospital, and the authority of the mayoralty enabled me to move quickly to secure its future.

Having a mayor gives voters a real choice about the future of their town or city. Often local elections are focused either on national politics (sending the government a message) or on who will speak up for a particular ward or neighbourhood. Strategic questions are often not even debated. Voters don’t get to weigh up who will be best at running the council, because the leader is chosen by councillors of the victorious party behind closed doors, once the election is over. Mayoral elections mean candidates cannot escape setting out their rival visions and policies for people to choose between.

Mayors have a higher public profile than council leaders. Research carried out after the first wave of elected mayors took office in 2002 showed that 57% of people could name their mayor, while a more recent study showed that only 8% could accurately name their council leader. People expect to be able to contact their mayor directly and voice their opinions. Possibly the truest word anyone said to me about the mayoral system was a resident who, after berating me for changing my hairstyle too often, said: “I don’t always agree with you, but I know who you are, what you are doing and why.”

A girl pointed at me and asked, 'Mummy, is she famous?' To which her mother replied​,​: 'Yes, dear, but only in Watford'

Achieving anything worthwhile means risking unpopularity, and judging when a public outcry is a sign that you need to rethink – and when, sometimes, a silent majority in fact supports you. Perhaps it is the lot of an elected mayor to end up as something of a Marmite figure. Once, while out canvassing, I found one person who told me I had “saved” Watford – and another, just a few doors down, that I had “ruined” it.

Voters keep your feet on the ground. One day I was stopped in Watford High Street by a woman who wanted to tell me, in robust terms, her views on the state of the town. She was with her young daughter, who pointed at me and asked, “Mummy, is she famous?” To which her mother replied: “Yes, dear, but only in Watford.”

• Dorothy Thornhill served as mayor of Watford from 2002-18