Tims have move on since I retired in 2002...but Assembler was still the most reliable......supported systems written in CICS Macro level assembler in Boots and Lloyds Bank treasury systems. You have complete command of what is happening. Also used Cobol, which was widespread. Can't say I have kept up with more modern languages,and I think many of the 'old' systems have long since been replaced with third party 'packages' that often have to be hacked about (aka modified...) to attempt the correct functionality.