Typically this process begins when the development team first visits the site. In the case of Gateholm we had been invited by the National Trust for Wales and by Cadw, the Welsh government heritage agency, to consider the site as a possible Time Team location. Taking the trip to the beautiful Pembrokeshire coast, the Time Team crew members felt optimistic about the archaeological mysteries and the potential to tell a good story. However, upon arrival it soon became clear that this site was not going to be quite as straightforward as we might have hoped.

Formerly a promontory, Gateholm was now an island. Only accessible at low tide, access to the island was described by one of our local contacts as 'a bit of a scramble'. This talent for understatement is shown up by the actual way to access the site; drive o the end of a long beach, walk along the long beach (at low tide only), clamber over rough boulders covered in seaweed, climb over spiky rocks, also covered in seaweed, climbup even bigger rocks to the base of the island, climb up a vertical surface to the top of the island, collapse in heap.

Once on the island there wasn't any doubt that the archaeology was truly amazing. Tracks and small buildings were just visible amongst the tussocky grass. After a good chat about possible targets and archaeological strategy to our friends from the National Trust and Cadw we then had to get down again before the tide came in.

It is one thing getting four people on foot who aren't carrying anything onto the island. Its quite another getting archaeologists, digging equipment, cameras and presenters onto the island. Clearly climbing wasn't an option. Time to call in the experts. Trevor Mussiah and his colleagues have been working in coastal rescue, the climbing world and generally doing difficult things for many years.They have plenty of experience of working with TV crews and planning seemingly impossible tasks like the one Time Team were about to attempt. Trevor needed detailed information about the coastline and several site visits before he could establish exactly how best to approach the challenge. The end result of all this work was a complex zipline. This needed to be secured on the mainland and the island, be able to take the weight of personnel and equipment and be angled correctly to ensure there would be enough momentum to carry any load safely across. Of course the line had to be manned at both ends so that somewhat nervous presenters and somewhat gung-ho archaeologists could be hauled up the rock face upon arrival.

The first time across on a zipline is always the most frightening. Several members of staff simply refused to use it. Those that did became quite expert towards the end of the project. However, even with such an efficient method of travel and with the high level of skill provided by Trevor and his team the time it took to get to and from the island was a real problem. In regard to the archaeology we had to rein in our ambitions somewhat but still managed to achieve an enormous amount over the three days.

Luckily Phil decided to work on the mainland. I can't see his hat surviving a trip on a zipwire - can you?