In 1953, the Anglo-Persian Oil Company developed a large oil refinery, Kent Oil Refinery, in the south of the Isle of Grain. A fuel depot with an attached port had existed there since 1928. From 1953, over ten million tons of crude oil were processed annually on the site. This led to the establishment of the oil-fired power station at Grain and dual-fuel capable Kingsnorth. In practice, Kingsnorth used coal. The refinery was closed on 27 August 1982, and work was transferred to other BP locations. The plant was taken over by British Gas plc, which used a small part of the site for the storage of liquefied natural gas. Three-quarters of the site remained unused.
During the construction of the Channel Tunnel, segments to line the tunnel from the British side were made on the site that is now Thamesport, before being delivered by railway to the site at Shakespeare Cliff, near Dover. As there was hardly any room at the site itself, the site on the Isle of Grain was chosen because of the links to the ships from Scotland delivering aggregate. Trains full of segments left the factory each day, travelling on the Hundred of Hoo Railway on the island before taking a circuitous route avoiding steep gradients before arriving at Shakespeare Cliff.
Container port
In 1987 British Gas submitted plans to use of the disused refinery site as a Container port. Building began in 1989. The risk capital financing of the £150 million project, named Thamesport, took place through the operating company Thames Estuary Terminals Ltd., later Thamesport Ltd. By March 1990 the enterprise had a capacity of approximately 360,000 TEU per year.
Land access
Land access to Thamesport was at first only by road. In time the railway line from Gravesend to the Isle of Grain was to be used. A goods station with track and transshipment facilities was developed at Thamesport. A government subsidy of £1.8 million was received. It started operating in January 1992.
Ownership changes
By the first half of 1990, the repayment of c. £100 million risk capital put the operator company Thamesport Ltd. into administration. The investment group Rutland Partners LLP acquired 95% of MTS holdings Ltd – the parent company of Thamesport Ltd – in December 1995 for £25 million and took over debts of £27 million. With the new owner, the port was further developed. The capacity increased to approximately 635,000 TEU per year. In 1997, with a turnover of £27.3 million, a profit of approximately £2.5 million was made. In February 1998 Rutland Partners LLP sold their interest in MTS holdings Ltd and small navigation company "Maritime Haulage" for £112 million to the Hutchison Whampoa Group. Hutchison Whampoa also operates two other important ports on the British east coast, Felixstowe and Harwich.
Deep-water port
In 2001 Thamesport was developed into a deep-water port. The harbour basin was dredged to a depth of at least, and the approach to a minimum depth of, at a cost of £3.5 million. In June 2008, its name was changed to London Thamesport.
Facilities
The heart of Thamesport is a deep water dock. The quay has eight gantry cranes, and can service vessels with draughts of. The temporary storage facility has capacity for 26,000 TEU; i.e. 13,000 standard containers. The container handling is semi-automatic, as the container tugs are manually operated. 635,000 TEU can be processed annually. In the long-term the capacity could be doubled. Although site constraints limit the maximum possible length of the quay to only, there is considerable scope for future development at Thamesport. The majority of this brownfield site remains undeveloped, and Thamesport Interchange has outline planning permission to build of logistics related facilities. Immediately to the north of Thamesport is a terminal for the import of aviation fuel. Thamesport will be well-placed if proposals for a new London Airport, either on the Isle of Grain itself, or on the Mayor of London's "Boris Island", come to fruition. Although the company appears confident of further development and a prosperous future, Thamesport is in danger of being eclipsed by the new and much bigger London Gateway port on the north bank of the Thames. London Gateway is now operational and is receiving 17 container ships per day. Satellite photographs of the Thamesport site appear to show that the facility is being dismantled; the large marshalling yard for containers is now empty. There are plans for a cement factory on the former container marshalling yard.
Land traffic
;Road Thamesport is connected to national road network by the A228. ;Rail The port also has from a connection to the single-tracked, standard gauge, freight Hundred of Hoo Railway. Two British rail freight companies – DB Cargo UK and Freightliner – currently have container services to Thamesport. In the first half of 2005 approximately 25% of traffic to and from Thamesport used the rail link.
