The project at the Grade II listed mill in York was launched four years ago and is aimed at ensuring flour is ground there for the first time in nearly 80 years.

The Lincolnshire-style "Ogee" shaped cap was lifted into place by a crane on Saturday after an initial attempt had to be postponed last week because of high winds.

The public were given the chance to see the newly fitted cap during an open day at the windmill yesterday.

The chairman of the Holgate Windmill Preservation Society, Bob Anderton, said: "To build and then fit the cap is the biggest task of the whole restoration, and it is wonderful to see it in place.

"We have had some really great comments from people who are so excited to see it on top of the mill and they have been really impressed by the quality of the workmanship. It really does make all the hard work worthwhile."

The windmill dates from 1770 but has been idle since it stopped grinding corn in the 1930s, when it was powered by electric motors. Organic flour will be produced from locally-grown grain when the restoration project is completed.

The cap was moved from the Network Rail site in York's Holgate district at 6am on Saturday before BT engineers took down telephone lines on Windmill Rise to allow it to be lifted into place. Millwrights removed the temporary roof and then carried out some minor brickwork repairs before the cap was lifted on to the top of the historic building by a crane by lunchtime.

The cap is being fitted with a lightning conductor and is formed from 28 Ogee-shaped oak spars, which have been clad with horizontal pine boarding followed by vertical boards of red cedar.

The old cap and brakewheel were removed in October 2006, and a fantail stage was last seen on the mill in 1939. It is hoped that the restoration will be completed in the autumn of next year.