US firm Paul Hastings is looking to double its London partner count by 2020 as it focuses on broadening its finance offering in the City.

The Los Angeles-headquartered firm, which first opened its doors in London in 1997 with ten lawyers, currently has 24 partners in London and is aiming to expand this to between 40 and 50 partners in five years.

Associate headcount is expected to grow proportionally so the firm's 80 lawyer headcount in the City could rise to up to 180 by 2020.

The bulk of the growth will be in finance, with leveraged finance expected to grow by up to eight partners in the next 12 months.

The firm also plans to add at least one more structured finance partner in this time-frame following this week's hire of Berwin Leighton Paisner's (BLP) head of structured debt and capital markets Paul Severs.

We've looked at areas in the US where we are very strong and sought to replicate and enhance those practices in London

The firm's London chair Ronan O'Sullivan said that Paul Hastings needed to be "more relevant and have more scale" in the City.

"We've looked at areas in the US where we are very strong and sought to replicate and enhance those practices in London rather than just bolting on new practices in an incoherent fashion. For the firm as a whole and London our broad finance offering is a key focus," he said.

The firm's key finance clients in London include Goldman Sachs, Deutsche Bank, JP Morgan, Societe Generale, CVC and Starwood Capital. New clients won this year include Etihad, Petra Diamonds and Singha (Europe) Breweries.

Leveraged finance and high yield are key priorities for growth. In New York, the firm already has 50 lawyers and 15 partners in this space.

"While I don't think we need to be that broad here in London we certainly need to be significant in terms of scale," O'Sullivan said.

In structured finance, the firm already has a team of between 10 and 15 lawyers headed up by Charles Roberts who joined the firm along with 24 other lawyers, including seven partners, in 2009. The team is currently focused on real estate structured finance but it is aiming to broaden this, O'Sullivan said.

"As we grow finance inevitably we will need more M&A, contentious and private equity lawyers. So the practices will swell around that," he added.

O'Sullivan said the market was driving his desire to expand the London office's finance practice.

"A lot of the large financings in Europe, particularly corporate financings, are being financed with a mixture of US and UK finance products. Part of the reason why US firms like us have been able to take the lead in that sort of world is because we can offer that mix," he said.

A lot of other firms are more established but aren't growing as significantly

When asked who he felt his competition in the finance space was O'Sullivan pointed to Latham & Watkins, Shearman & Sterling, Weil Gotshal & Manges and Gibson Dunn & Crutcher.

"Gibson and Paul Hastings are at a similar stage – we are both investing heavily – a lot of other firms are more established but aren't growing as significantly," he said. "We don't necessarily bump up against each other but we are the US firms in London most similarly situated in terms of financial performance and ambition."

Paul Hastings posted a 6.3% increase in global revenue in 2014 to reach the $1bn (£652m) mark for the first time in the firm's history.

Profit per equity partner (PEP) also increased by 8.5% to $2.36m (£1.53m).

Gibson Dunn also saw revenue rise 5.7% in 2014 to $1.47bn (£900m) while partner profits rose 3.2% to $3.04m (£2m).

Elsewhere, Paul Hastings will continue to invest in its continental Europe offices, where it has 30 partners based across Paris, Milan, Brussels and Frankfurt but has no plans to open additional offices.

Overall, London is going to "drive the growth in Europe", said O'Sullivan, adding that he was "not complacent" about the path ahead.

He said: "We've got competitors everywhere and clients are getting more and more demanding – so we're extremely focused. The challenge for us is to maintain our momentum and trajectory."