Mexico's President Enrique Pena Nieto ended his three-day state visit to Britain on Thursday by overseeing the signing of deals that boost ties between the two countries in energy, including a $1 billion oil agreement.
Under the deal, Britain will provide Mexican energy firms with a $1 billion credit line (908 million euros) for buying British technology.
Pena Nieto was joined by Scottish Secretary Alistair Carmichael in the city of Aberdeen, the hub of Britain's North Sea oil industry.
The deals also covered carbon emissions and an agreement between Aberdeen University and Mexican state oil giant Pemex to help train specialists.
British business minister Matthew Hancock said the deals opened up "unparalleled opportunities for partnership across business and education."
The Mexican leader earlier Thursday said farewell to Queen Elizabeth II after staying two nights at her Buckingham Palace residence in London.
While in the British capital, Pena Nieto was honoured with a state banquet after arriving at the palace in a horse-drawn carriage with the British monarch.
He met with British Prime Minister David Cameron on Wednesday, where the pair discussed human rights in Mexico and energy ties as part of European efforts to reduce dependency on Russia.
Also on Wednesday, he met with business leaders, as British drinks giant Diageo announced a total $400-million investment in a Mexican tequila plant.
The president's visit to Britain is part of efforts to burnish his international image as he struggles with falling approval ratings and relentless drug violence at home.
The disappearance and alleged murder of 43 college students by a police-backed gang galvanised protests in Mexico, and on Tuesday Mexicans demonstrated in London calling on Britain to address the "human rights crisis".
In a speech on Thursday, Carmichael stressed the importance of "respect for human rights".
"As we strengthen the links between our countries I am sure that this will continue to be a feature of our dialogue," he said.