BT, the telecommunications titan, has had its rating upgraded by UBS after solid fourth quarter results. While underlying revenue declines matched previous quarters, the broker notes that underlying cost savings accelerated with strong savings in its core operations.Key performance indicators were "particularly impressive", according to UBS, which highlights slowing line lossed and high broadband additions."BT's positive earnins momentum contrasts with mobile-driven earnings cuts for other telcos," the broker said.UBS's recommendation now stands at a 'buy', from 'neutral', while the target price is hiked from 200p to 230p.---BC