Channel 4 Time Team star Phil Harding was to have planted a waymarker at the five-acre Castle Garden on Saturday afternoon, but didn’t show up.

Instead British Trust for Conservation volunteer Alan Belcher, who with other members has done extensive voluntary work on the project in recent years, stepped into the breach to perform the ceremony.

Di Keal, who has spearheaded the project for eight years, said: “We don’t know why Phil didn’t turn up. Several months ago he agreed to come back to Malton, where he had filmed with Time Team in 1996, to officially open the garden. I only spoke to him about a week ago and everything was fine then.”

About 75 invited guests and 200 people altogether attended the ceremony and walked around the garden, which is classed as a Scheduled Ancient Monument because below ground are the remains of part the Derventio Roman fort, Malton Castle and a Jacobean Prodigy House.

A grant from Yorventure, the funding branch of Yorwaste, paid for much of the work, with support from Ryedale District and North Yorkshire County Councils and the Big Lottery. The park opens from 8am-8pm on Saturdays and Sundays until next month, when work on the steps to it from Castlegate should be complete. It will then open daily.