Harry, who was representing the Queen, was joined by senior politicians including the Prime Minister and Labour leader Ed Miliband at a Westminster Abbey service celebrating the life of Mandela, who died on December 5 aged 95-years-old.
Nearly 2,000 people attended the service which featured South African singing and drumming and an address to the congregation by the country's deputy president Kgalema Motlanthe.
The Most Rev Tutu, the former Archbishop of Cape Town, also made a speech and thanked the "splendid" and "amazing" anti-apartheid campaigners for their efforts in changing the "moral climate" over apartheid.
He said: "What would have happened had Mandela died in prison as was the intention and hope of the upholders of apartheid. I suppose most would have regarded him as no better than a terrorist - after all, persons in high positions in Britain and the US did dismiss him as such."
Archbishop Desmond Tutu has been awarded a £1.1 million prize for "affirming life's spiritual dimension".
The 81-year-old landed the 2013 Templeton Prize for his lifelong work in advancing spiritual principles such as love and forgiveness which have helped to liberate people around the world, organisers said.
The former Anglican archbishop of Cape Town said: "When you are in a crowd and you stand out from the crowd it's usually because you are being carried on the shoulders of others.
"I want to acknowledge all the wonderful people who accepted me as their leader at home and so to accept this prize in a representative capacity."
The Templeton Prize has been the world's largest annual monetary award given to an individual for the past 40 years.
Multi charity coalition IF claims that tackling the 'corporation tax gap' by multinational companies could help developing countries to raise enough revenue every day to save the lives of 230 children under five.
We should be proud of the great strides we are taking as a world to reduce poverty and tackle infectious diseases, but it is still the reality that more people die each year from hunger than from Aids, malaria and TB combined.
In a world where there is enough food for everyone, this is nothing short of a scandal.
We need a concerted effort from governments, civil society and philanthropists to tackle the root causes of this problem and together build a world where no child has to go hungry.