[traceroute66]

> What's going on near london?

As others have said, more likely dodgy methodology by gpsjam than anything sinister.

For example:

    - As well as being an active airfield, Heathrow also houses a small number of maintenance bases (e.g. BA have one, United are currently upgrading an ex-Virgin one etc.). I'm not familiar with aircraft maintenance, but I suppose there could easily be scope for RF signals related to test procedures to be leaky and be picked up by geeks.

    - There is also Farnborough.  Whilst Farnborough is predominantly a GA (General Aviation, i.e.  private jet) airfield, it is also on of the many homes of QinetiQ in the UK.  QinetiQ being a defence contractor.  So again, one could speculate about leaky test signals.