Experts fear the result will be a temporary shortage of airline pilots, which might force airlines to take on the cost of pilot training.

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BP's traders of buying up supplies of propane towards the end of America's winter heating season, in an effort to create a temporary shortage.

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If there was a temporary shortage, you temporarily paid higher wages.

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So far, 77 companies have qualified for the programme, which is designed to help firms that have solid business prospects, but suffer a temporary shortage of cash.

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While the temporary shortage is a call to be smart and judicious with helium use in the very short term, it does not justify the alarmist rhetoric of those who have called for an end to balloon sales.

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But on the subject of professions suffering from shortages, such as nursing, Mr Green said there was "no reason why Britain should have a permanent shortage of nurses" and any use of foreign workers should be temporary.

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