Conservative politicians are calling for a ban on tube strikes - arguing that they should be replaced with a compulsory mediation process.
A report, published by Conservative members of the Greater London Authority, claims that strikes have an "immense" impact on the UK economy - and should therefore be "outlawed".
Instead, an impartial judge would decide on a settlement.
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A former health and safety chief said building regulations are confusing and the profession suffers from competence issues.
The tiny card, which is 15 microns by 20 microns, even includes an intricate inscription of a snowman and seasonal messages.
Police say they have traced four drivers who are thought to have hit the woman, and added that a fifth vehicle may also have been involved.