Vectra 1,9 cdti, engine noise (POP) and now no acceleration

[geordie exile]

Hi All, new to the forum so this may have been covered before.

Vectra 1,9 cdti 204000 miles (K200). 54 plate

Traveling home from work, a POP sound from the engine and loss of acceleration, was able to struggle home at a max of 2000 RPM. I am now very worried.