This is one of my favourite photos of my dad. Ever.

It was taken onboard the MV Negros, an old wooden ship that sails along the Amazon from Belem to Manaus in Brazil.

The journey took four days. There was no onboard accommodation, as such, just a large upper deck with hooks for passengers to hang their hammocks.

The locals had a hammock to hand for this very purpose. We had to buy ours from a market, moments before we set sail.

By the time we finally clambered on board all the good spots were gone.

The last available hooks were right in the middle, where space was at a premium and conditions their most cramped and claustrophobic.

Thankfully, the sides of the upper deck were open. There was a constant cooling breeze. And best of all, we could lie in our hammocks and watch the world of the mighty Amazon go by.

Things got a little trickier at night. A couple of working girls had joined the boat to ply their trade and when things got a little frisky, a chain reaction was set off along the whole line of hammocks. Being right in the middle, my father and I got it from both ends, so to speak.

In that way, the whole upper deck was like a giant Newton’s Cradle – the pendulum toy featuring five hanging silver balls that was such a staple of executive desks in the Eighties.

Except it wasn’t clacking silver balls demonstrating Newton’s theory on the conservation of momentum and energy. It was humans, trying to sleep in their hammocks.