The FTSE showed little reaction to Chancellor George Osborne's Emergency Budget, narrowing only slightly by 0.2% as he finished delivering it.
The index registered a 1.5% daily loss when Osborne began, narrowing slightly to 1.3% by the time he ended.
By 1.30pm it was at 5228.41 points.
By 2.15pm it had closed to a 1% loss on the day, at 5244.25 points.
The pound weakened slightly against the US dollar, with a 0.25% fall before Osborne spoke today, widening to 0.31% by the time he finished.
Sterling gained ground soon thereafter.
It was up 0.2% against the euro.
Prices of all bar two of 36 gilts rose as he presented the Budget.
Many managers feared the pound, shares and gilts could all fall sharply if Osborne's measures were not strict enough.
Bank shares jumped as he proposed a levy on banks not as harsh as many feared.
Lloyds Banking Group, Royal Bank of Scotland, Barclays, HSBC and Standard Chartered all jumped since around 1pm.
Lloyds Banking Group rose 4.6% to 58.55p by 2pm. Barclays was also up, by 2% at 310.25p; HSBC rose by 0.7% to 656.6p; and Royal Bank of Scotland gained 3.6% to 47.36p.
The tax on large UK banks from January is expected to raise over £2bn annually.
Osborne pledged to work for global agreement on the levies. Germany and France will also impose similar taxes, he says.
The levy will also apply to the UK operations of foreign banks.
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