LONDON, Aug 19 (Reuters) - Pascal Soriot, the chief executive of COVID-19 vaccine maker AstraZeneca (AZN.L), was Britain"s highest paid company boss in 2020, a year when the average FTSE 100 leader saw their pay fall by almost a fifth, a report on Thursday showed. Soriot, whose handling of the pandemic response has drawn criticism despite the company producing its vaccine at cost price, took home 15.45 million pounds ($21.25 million), a report from the High Pay Centre said. That compares with median pay for CEOs in Britain"s flagship stock index of 2.69 million pounds, down from 3.25 million pounds in 2019, the report found, but still 86 times the median earnings for the average UK worker. Shareholders had demanded bosses share the financial pain as companies across a range of sectors experienced a tough year, with lockdowns in many countries hitting sales. The proportion of companies paying bonuses dropped to 64% from 89% in 2019, while 77% paid out long-term incentives based on performance over the previous 3-5 years, compared to 82% the previous year. Of the nine companies which took public money through the British government"s furlough scheme, the average CEO pay was 2.2 million pounds. "CEO pay packages are designed to reflect the experience of shareholders, employees and other stakeholders so in one sense the lower pay levels this year show the system working as intended," said High Pay Centre Director Luke Hildyard. "On the other hand, these are still very generous rewards...at a time when, in general, government support for the economy has probably been more important to the survival and success of the UK"s biggest companies than the decisions of their executives." Rounding out the top five earners were Experian"s Brian Cassin, with 10.3 million pounds; CRH"s Albert Manifold, with 9.92 million pounds; Reckitt Benckiser"s Laxman Narasimhan, with 9.24 million pounds, and Berkeley"s Rob Perrins, with 8.03 million pounds, the report said. ($1 = 0.7271 pounds)