Diplomatic immunity is intended to prevent the host country (the UK) from subjecting diplomats to unreasonable detention, imprisonment etc, or to protect them from work done as part of their job (the host country might consider it spying).
Responsible countries either waive the diplomatic immunity, or prosecute the offender in their own courts. The USA has done neither.
In 2002, a Colombian diplomat had his immunity waived, allowing the UK to prosecute him for manslaughter. [1]
Responsible countries either waive the diplomatic immunity, or prosecute the offender in their own courts. The USA has done neither.
In 2002, a Colombian diplomat had his immunity waived, allowing the UK to prosecute him for manslaughter. [1]
[1] http://news.bbc.co.uk/2/hi/uk_news/england/2284320.stm