英国在 G7 内已是融资成本最高的主要经济体之一，公共部门每年利息支出已超过£100bn，财政压力持续累积。资深机构估计，3月预算后加息使 Rachel Reeves 的财政「预留空间」可能由£23.6bn降到约£18.5bn，且仍未计入实质GDP放缓与更高通膨的进一步冲击。全球亦同步受中东冲击，30年期美债一度冲到5%，显示长端资金成本扩张已成共振。
在地方与分权选举前，市场重估英国央行（BoE）路径，交易员改为押注年内再加息2到3次、每次0.25个百分点，以压制反弹通膨；早前预期则偏向加快降息。政治不确定性因 Sir Keir Starmer 及英国工党压力上升而被纳入债市定价，投资人以较高政治风险溢酬要求回报。伦敦外汇市场中，买入 sterling put 的比例达70%，反映英镑偏弱预期。财政部虽新增12个月国库券并引入回购便利、扩大短端市场流动性，英国债券仍受政治与通膨双重压力拖累。
UK long-term borrowing costs rose sharply on Tuesday amid a deepening Hormuz crisis and higher oil prices, driving yields to their highest level in nearly 28 years. Thirty-year gilt yields jumped by 0.14 percentage points to 5.79% before easing to 5.74%, while the 10-year gilt rose to 5.11%, close to the prior 18-year high of 5.12%, then sat at 5.06%. The report says gilt prices fell as yields rose, and UK long-end sovereign debt has become the weakest major bond market since the conflict began.
The UK already has the highest borrowing cost among G7 peers, with annual debt interest already above £100 billion, adding to fiscal strain. Capital Economics estimates that higher market rates since the March fiscal statement could reduce Chancellor Rachel Reeves’s headroom from £23.6 billion to about £18.5 billion, even before weaker real GDP growth and higher inflation are included. Globally, oil in a Middle East conflict backdrop also lifted pressure across long yields, with US 30-year treasury yields reaching 5% for the first time since September.
Before this shock, investors had expected the Bank of England’s Monetary Policy Committee to cut rates, but the scenario shifted toward two to three quarter-point hikes by year-end to counter resurging inflation. Political uncertainty before UK local and devolved elections is now a pricing factor, as Sir Keir Starmer’s Labour faces potential losses and a possible political shift. Traders have increasingly positioned for a weaker pound; CME data shows sterling-dollar puts made up 70% of weekly options activity. The Treasury introduced 12-month bills and new repo support to deepen short-end liquidity, but UK gilts remain under pressure from inflation and election risks.