The site, sealed off by metal sheeting from the road bordering the field, had played host for three days to the hopes of the Sinnott family that their eight-year ordeal was coming to an end.

According to informed sources, the dig was launched on foot of information which had surfaced as a result of six arrests made in September and of investigations which have continued since then.

Gardai were made aware of the possibility that the missing woman's remains were buried in the field two months ago. However, as a crop of sugar beet was planted in the 15 acre plot, a decision was taken to wait until this had been harvested.

When the crop was harvested two weeks ago, arrangements were made for more than a dozen gardai, including detectives stationed in Wexford and gardai from the National Bureau of Criminal Investigations and the technical bureau, to excavate the site.

Mapping experts were called in to recreate the original field on paper and, on Thursday last, investigators used geo-imaging equipment to establish if any of the earth had been disturbed along the area formerly occupied by the ditch. The equipment established several anomalies in the soil along a 40sq m area.

On Friday morning, at approximately 9am, gardai sealed off the site and the dig began. The equipment used meant gardai knew exactly to what depth they needed to dig at each point and precluded the possibility of the excavation being open-ended.

At approximately 1.30pm yesterday, Detective Ken Piper of Wexford garda station told members of the Sinnott family that all potential locations for Fiona's body had now been excavated.

An uncle of the missing woman, Gerry Sinnott, said afterwards that, while the family were disappointed, they had 'never really expected anything different'.

Another uncle, Joe Sinnott, added: "We know the gardai are not giving up and we have taken great comfort from that.

"Fiona's killer and anyone who helped that person know this as well. The gardai will not give up and we, as a family, will not give up. He will make a mistake and his day will come."

In a brief statement given by Supt Mark Kerrigan, he agreed that nothing unusual had been detected at the site.

He added that a review would be carried out later in the afternoon to assess whether or not the dig would be wound down completely.