Germany's Allianz in deals that could top £800m is buying businesses from LV and Legal & General that will make it become Britain's second-biggest general insurer behind Aviva.

The deals will boost Allianz's UK premium income to more than £4 billion and its market share to 9% and come as tougher capital rules prompt companies to sell assets and focus on growth areas.

Allianz said its UK unit would pay up to £578m for the remaining 51% stake in its LV joint venture with Liverpool Victoria Friendly Society (LVFS).

It also said it would pay an initial £242m for the general insurance business of Legal & General. A spokesman said this could rise to closer to £300m.

Expected to complete by the end of 2019, the deals will place Allianz among the top-four home insurers and give it 12 million UK general insurance customers, it said.

"With these two transactions, we are pleased to demonstrate our further commitment to the UK market," said Allianz SE management board member Niran Peiris.

L&G's decision to shed the 'G' part of its name marks the end of a series of disposals for Britain's third-biggest insurer.

The bulk of the business being bought concerns home insurance, with a small book of pet insurance. 

L&G said it would retain the profit from a separate book of business including professional indemnity insurance, which Allianz is not acquiring.

The deal is expected to increase L&G's Solvency II ratio, a key measure of its capital strength, by 2 percentage points, it said in a statement.

"Selling the General Insurance business is the right decision for our customers and shareholders," L&G's chief executive Nigel Wilson said.

"We continue to focus on delivering against our strategy, allocating shareholders' capital rigorously. We are market leaders in 10 UK markets and have a growing presence in the USA and an emerging presence in Asia," Mr Wilson said. 

"Deploying capital in these businesses will deliver better outcomes for all our stakeholders," he added.

LV, which also said it wants to use the money to help expand its life insurance business, said it would disclose the impact on its capital position later in the year.

"We have successfully grown the value of our general insurance business to in excess of £1 billion and this deal enables us to realise that value for the long-term benefit of our members as well as strengthening our overall capital position," its group chief executive Richard Rowney said.