The government minister in charge of drawing up strict new laws on strike action would not have been elected if the same rules applied to him.

Sajid Javid, the business secretary, has unveiled plans to ban strikes by key public sector workers unless they are supported by at least 40 per cent of all of those eligible to vote.

But taking a look at the results of his own Bromsgrove constituency in May's general election reveals that he himself was supported by just 38.3 per cent of the 74,000 people eligible to vote in his seat.

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So Mr Javid, like the vast majority of the Tory MPs who are backing the crackdown on trade union industrial action, would have failed to be elected if the rules he is applying to key public sector workers applied to him.

The strict new laws, which could come into force as early as next year if approved by MPs in the autumn, will cover key public sector workers such as nurses, teachers, fire fighters, train drivers and Border Staff.

The proposed new law on ballot support would have kept some of London Underground open in the most recent strike (Corbis)

Meanwhile in other sectors that are not deemed as vital public services, strike action will be curtailed with a new 50 per cent turnout threshold for industrial action to be legal. There are even some MPs who would fail to reach this criteria if it was applied to parliamentary elections, including Tristram Hunt, the shadow education secretary, whose Stoke-on-Trent Central seat saw a turnout of just 49.9 per cent.

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If the proposed changes had been in place before last week's London Underground strike, which caused widespread chaos across the capital, two of the four unions on strike would not have reached the threshold and would have been banned from going ahead with industrial action. Transport for London said it could have put on a limited service if this had been the case.

Similar moves to clamp down on strike action was proposed by the Tories in the last government but the Liberal Democrats blocked the plans.