The best advice is in the Highway Code - drive with care even if roads have been salted, be prepared for road conditions changing over short distances and take care when overtaking gritters.

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An independent expert, Sir David Bell, had ruled that the First Minister had not broken the ministerial code with regard to the issue of legal advice on Scotland in Europe.

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On top of the Code itself are the related Treasury Regulations, Revenue Rulings, Technical Advice Memorandums, Revenue Procedures, etc.

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