Harry Potter fans have forced a new multimillion-pound power cable between the UK and Ireland to be relocated after complaining it would desecrate the “grave” of Dobby, a fictional elf.

The character was laid to rest on Freshwater West beach in Pembrokeshire, Wales, in the film Harry Potter and the Deathly Hallows. Fans of the wizard series come to leave stones reading “Here Lies Dobby” despite being asked not to by the land owner, the National Trust, because the beach is an ecologically sensitive site.

The £430m Greenlink interconnector, which links the National Grid to Ireland, was initially going to pass through the site of the “grave”, the project manager Simon Ludlam told the Energy Revolution podcast.

Fans became aware of the plans after Ludlam pointed out where the 125-mile (200km) cable to County Wexford would go underground at Freshwater West during a BBC interview. “We did the shot, we finished, I went back to London, and they then aired it a couple of weeks later. And we got hundreds of calls, I mean, hundreds of calls.”

Ludlam said he did not know who Dobby was, and became confused by the calls the company received, saying a colleague told him: “Apparently we’re going to go straight through Dobby’s grave”.

“I said: ‘Dobby, who’s Dobby? I don’t know Dobby?’ I said: ‘He’s a fictitious character in a fictitious book, the whole thing is fictitious, what are you talking about?’”

He said the colleague told him: “No it’s very, very serious.”

The firm then enlisted planners to find a new route that avoided the supposed grave. “A lot of people were very happy about that, and the project is now going [ahead] and Dobby’s happy.”

In the end, he said, “we went quite close to some real Bronze Age remains, but we avoided Dobby’s grave”.

The Bronze Age remains include urns associated with human burial.