In June 1982, Diego Maradona was signed for a world record fee of £5 million from Boca Juniors. In the following season, under coach Luis, Barcelona won the Copa del Rey, beating Real Madrid. However, Maradona's time with Barcelona was short-lived and he soon left for Napoli. At the start of the 1984–85 season, Terry Venables was hired as manager and he won La Liga with noteworthy displays by German midfielder Bernd Schuster. The next season, he took the team to their second European Cup final, only to lose on penalties to Steaua Bucureşti during a dramatic evening in Seville.

Answer this question, if possible (if impossible, reply "unanswerable"): How much was the signing payment for Diego Maradona?
£5 million