Four leading technology companies are due to meet the British government in the wake of an attack last week in London.

The attacker used instant messaging service WhatsApp in the minutes before he killed four people at Westminster - but the messages cannot be decoded.

Facebook - which owns Whatsapp - will attend the meeting, along with representatives from Google, Microsoft and Twitter.

Al Jazeera's Neave Barker reports from London.

Europe, United Kingdom, Politics