OIL GIANT BP provided further proof of sharp reversals in the oil industry, unveiling a 46% slump in fourth-quarter profit to $2.2bn (£1.5bn). Chief executive Lord Browne said it had been 'tough going', as oil fell more than $10 a barrel, gas prices dropped and refining margins were squeezed. Full-year profit was $13.2bn, a fall of 7%. The year's dividend is up 7% at 22 cents.