BBC Master 512
This is a close-up of the 80186 board.
In addition to the big square chip in the middle, an Intel 80186, we can see the Tube ULA chip and two Master 512 boot ROMs. There is 512K of RAM on the board and various 74 series logic chips and resistors and capacitors.
The legend reads "0243,200 ISS.1 ACORN COMPUTERS 80186"