Qatari Emir Tamim bin Hamad Al Thani was met with a barrage of protests as he arrived at the House of Parliament to address a British pro-Qatari group in controversial circumstances.
Dozens of protestors gathered ahead of the arrival of the Qatari leader outside parliament. The demonstrators were accompanied by a number of vans decorated with the slogan "Qatar is a terrorist state" that have roamed London in the days leading up to the visit.
Protests were also held outside the Qatari embassy in Mayfair, where demonstrators waved posters proclaiming: “If a country was accused of paying $1 billion in a ransom to terrorist groups… then why is the UK government rolling out the red carpet for the Qatar emir?”
Al Thani addressed a delegation of British MPs and Lords in the House of Parliament on Friday afternoon, ahead of the British parliamentary group on Qatar's annual general meeting.
The All Party Parliamentary Group on Qatar, led by MP Alistair Carmichael and which gave the emir a platform, had accepted more than £50,000 (Dh250,000) from Qatar's foreign ministry in 2016 for a visit to Doha.
The speech within the parliament was expected to convince politicians of the value of the country's relationship with the United Kingdom, though it was closed to the general public and media.
Earlier in the day, Sheikh Tamim travelled to Mansion House in London's financial district for meetings with a number of British business leaders.
The 38-year-old emir's visit was mired in controversy in the days leading up to the leader's arrival, with the hashtag "#OpposeQatarVisit" trending across the capital.
Social media clashes also saw activists criticising the Qatari state's support for Houthi rebels fighting in Yemen.
The two-day trip to London will see him meet with Prime Minister Theresa May on Tuesday. Activists have urged Mrs May to challenge the Qatari leader on issues, including the state's funding of terror groups, and its controversial hosting rights for the 2022 football World Cup.
A coalition of Saudi Arabia, the UAE, Bahrain and Egypt has led an economic blockade of Qatar since last year in response to the state's continued support for extremist groups in Syria and interference in the internal affairs of its neighbours.
This month, the BBC revealed new evidence that Doha had paid a $1 billion ransom to a Shiite militia for the release of 28 Qataris kidnapped while hunting in Iraq.