The decision follows active escorting trials carried out by the Authority at the end of last year, which proved conclusively that under certain circumstances laden tankers could be stopped and turned by a tug attached by a towline. A two-day escorting trial was carried out in November 2001 with the tug Anglegarth and the chartered C H Sorensen tanker Magnitude to establish and record the ability of the tug to act upon the speed and course of the loaded tanker. Over the two days, a total of 17 runs were conducted in a designated trial area south of St Anne's Head, off the Pembrokeshire coastline, designed to establish the tug's ability to influence the speed and direction of the tanker at speeds between 4 and 12 knots. The trials tested many different aspects of active escorting including engine speed, speed through water, strain on the fittings, helm order, heel on tug and the stress on the tug's winch, all carried out over various speed runs. The tug was used both to stop and steer the ship including a run at 12 kts when the ship was successfully stopped. The weather during the trials was good, with a force 2-3 wind and a low swell. Connect and disconnect trials were carried out in 2.5m of swell.

Wijsmuller Marine Ltd. (part of the Svitzer Wijsmuller Group) provided the tug and the Maritime Research Institute Netherlands (MARIN) undertook the fully computerised instrumentation of the tug and the tanker. Technical support was also provided by the research department of the tug builders Damen Shipyards and Wijsmuller Engineering.

MARIN's analysis showed that the trial was an unqualified success and the Anglegarth proved conclusively that a tug of her class and type (Damen ASD 3211) is capable of stopping and turning a laden tanker at speeds up to and including 12 knots.