The Cornish couple who make Britain's blue plaques

Britain's blue plaques are celebrating their 150th anniversary this year. For the last 32 years they've been handmade by a couple in Cornwall.

Frank Ashworth and his wife Sue make the signs which celebrate the links between famous people of the past and the places they lived and worked in.

Frank says: "Making a plaque is quite a difficult and complicated process. You have to discipline yourself to a certain concentration.

Freddy Mercury was a very special person and I certainly think he deserves a plaque. And it is satisfying to organise a process that can lead to success.

It's not boring...you might say it is repetitive, but it is a challenge. We pride ourselves on the degree of craftsmanship we obtain to. We won't do second best."

Frank and his wife Sue have been making these distinctive plaques for English Heritage for the last 32 years.

They celebrate the links between Britain's most notable figures and the buildings which they and worked in.

Using special tools, clays and glazes they've made plaques for the likes of Jimi Hendrix, John Lennon and Alfred Hitchcock.

Sue says: "I think the most special thing is that one is involved in this very careful process to try and do something worthy of the people who are bought to our attention - I do enjoy working in my own time and not being under pressure - the pressure comes from finishing whilst the clay is in the right condition."

Every time when you get into it, you do the very best you can. That is just choosing to be a craftsman."

The plaques can be seen all across London - and are awarded to people who have been dead for at least 20 years. Frank and Sue have 300 under their belts - so next time you spot one, you'll know where it came from - 300 miles west on the banks of the River Fowey.

You can watch Francesca Carpenter's report here: