BP has been taken to the UK high court by dozens of Colombian farmers Reuters

More than 100 Colombian farmers are taking on oil major BP in a London courtroom in a potential landmark environmental legal case.

The farmers, also known as "campesinos", have accused the British company Equion Energia, previously known as BP Exploration (Colombia) Ltd, of being negligent when it built the Ocensa oil pipeline.

The farmers say the pipeline ran though their properties and caused serious damage to the land, crops and property and are seeking around £18m ($29m, €23m) in compensation.

The UK high court trial, launched on Wednesday, is due to last for four months. It is the first trial BP has faced in a British court over its business practice overseas. It is also the first time a British oil company has faced litigation in the UK over environmental damage to private property overseas.

The trial is taking place weeks after a US court found BP had acted with gross negligence in the 2010 Deepwater Horizon disaster.

The farmers' lawyers have said they did not understand the agreements signed with BP Exploration (Colombia) Ltd and said they were not provided full and fair compensation for environmental damage under the deals.

They claim that the construction of the pipeline caused severe soil erosion, reduced vegetation coverage and damaged water resources, thus reducing the productivity of the farms.

A separate group of Colombian farmers reached a settlement with BP for alleged environmental damage but BP has decided to fight these claims in court.

BP has released a statement saying it was confident in its legal position and would fight the case.

"The Ocensa pipeline project in Colombia involved significant steps being taken at the time of construction to engage with local communities, make appropriate compensation payments and ensure that the land the pipeline traversed suffered no material damage," the statement said.

"BP believes that these measures were effective and that the construction of the pipeline was carried out to a high standard," it said.