Never ever use a screwed connection under a floor. These type of junction boxes are fine in a cupboard or in a loft (above the insulation) where you can access them and see them, but under a floor they can become loose all by themselves and start arcing causing a heat build up then fire.
This person managed to fit a 20A lighting Junction Box (JB) to a 32A ring main. He needed 6 connections, so he’s added some small connector blocks into the JB to maintain the ring main. Hat’s off to him, he kept the ring main intact, but put a seriously weak link in it!!
Always use a maintenance free junction box under floors etc, with spring loaded contacts and a cord grip. They will never come loose and fully comply with the electrical regulations.