Relatives and campaigners hope Labour will usher in a step-change in the handling of hostage cases

Gurpreet Singh Johal is sitting in a London hotel lobby the night before he is due to meet David Lammy.

He recalls in his soft Scottish burr that this will be the fifth UK foreign secretary he will have seen in his quest to secure the release of his brother, Jagtar, who has been detained in Indian prisons for seven years, with the case making virtually no progress.