It’s the mysterious tale of the missing links – vanished solid gold crests worth thousands of pounds and tarnished civic pride.

At its heart is the historic solid gold chain worn by generations of mayors of Gillingham and what happened to it after it was given to the Royal Engineers Museum when the borough council was abolished in 1998.

The alarm has been raised by at least three former civic heads who have noticed that the chain, which now forms part of a display of civic regalia at Rochester’s Guildhall Museum, has shrunk by half its original size.

Six of the 11 gold shields bearing the names of former mayors have disappeared, as have the intricate links between them.

Also missing are the gold letters of “a” and “m”, which completed the spelling of the name “Gillingham” in the chain.

Several retired mayors are demanding to know what has become of the valuable missing pieces that once hung proudly round their necks.

They include one who is terminally ill, and says his dying wish is to get to the bottom of the mystery.

An Army spokesman insisted this week: “We received the chain in 1998, and it is in the same condition now as it was then.”

However, when the town’s last mayoress, Diana Smith, accompanied her husband and the chief executive to deliver the civic regalia to the world-famous museum in Gillingham she said it “was definitely twice as large”.

Another former mayor, Paul Harriott, was shocked when he was invited to a viewing of it at Rochester’s Guildhall Museum, where it is currently on loan for a year.

He said: “It’s more like a necklace. It used to hang down to the navel, but you would struggle to get that over your head.”

The collection, which included gold brooches, pendants and the mace as well as the chain, which is believed to date back to 1850, was insured for nearly £100,000.

The official handover was on March 30, 1998, the day before the council merged with Medway to become a unitary authority.

The collection was covered by an agreement signed by chief executive John McBride and the then Royal School of Military Engineering commandant.

The contract said : “The Corps shall keep the goods safe and shall ensure that the goods are maintained in their present condition.

“It shall be a condition of the transfer of the goods that all goods shall be held by the Corps or be displayed in the Royal Engineers Museum in Gillingham or used for the purpose of the Corps.”

Ken Webber, who has served as mayor of Medway and Gillingham, said: “At the time there was a bit of angst from people in Gillingham who did not want to be part of Medway and did not want other people to get their hands on our treasures. The council also donated £10,000 for a smart glass display box for exhibits.”

Mr Webber, a former sapper and member of the Royal Engineers Association, said the museum was ideal. It was secure, in the borough of Gillingham and where the public could see the regalia on display.

Diana Smith, whose late husband, George, was the mayor in 1997/98, said she tried in vain to find the chain in 2008 when she was taking a group of Korean veterans on a tour of the museum in Prince Arthur Road.

She wrote to complain that it was not on show and a high-ranking officer replied that there were plans to re-house it in an annexe.

Mrs Smith, a former Gillingham councillor, said: “All I can say is that when we took the regalia over in the mayor’s chauffeur-driven car, it looked nothing like it does now.”

The case has also been taken up by the current mayor of Medway, Cllr Barry Kemp, who wears a close replica of the Gillingham chain.

Cllr Kemp said: “While it is a shame that the original mayoral chain of Gillingham is not complete, it is not now, nor has ever been, property of Medway Council. Ultimately, it is the business of the current owners to investigate any loss which they perceive may or may not have occurred since the ownership was vested.”