* Gold tops $1,300; those priced in euro, pound highest since 2013

* Base metals also tumble as risk assets dumped

(Updates throughout)

By Manolo Serapio Jr

MANILA, June 24 (Reuters) - Gold jumped 5 percent to the highest in nearly two years and oil futures slumped below $50 a barrel, as official results so far from a British referendum pointed to a victory for a campaign to exit the European Union.

Copper slid more than 2 percent to come off a seven-week high and grains also retreated as results from a referendum on Britain's 43-year EU membership poured in. China-traded commodities barely reacted, with iron ore and rebar futures largely steady.

Gold's climb tracked those of other safe-havens such as bonds, as the British pound collapsed.

"Because this Brexit is seen as an extreme risk event, it tends to attract a lot of interest in gold," said Vishnu Varathan, senior economist at Mizuho Bank.

With results in from 298 of 382 voting districts plus partial BBC Northern Irish figures, those in favour of ending Britain's 43-year EU membership were on 51.8 percent of the vote, while those wanting to stay were on 48.2 percent, based on Reuters calculation.

Spot gold was up 4.7 percent at $1,314.22 an ounce by 0336 GMT, after hitting $1,318.60, its strongest since August 2014.

Gold had benefitted from fears of the 'Brexit' vote winning the referendum ahead of Thursday's polls, with some concerned it could tip Europe back into a recession, putting more pressure on the global economy.

That could curb demand for raw materials from oil to copper, dragging down prices again just as many were regaining favour in recent weeks.

If Britain becomes the first state to leave the European Union, it would be the biggest blow to the 28-nation bloc since its foundation.

The EU would be stripped of its leading free-market advocate and one of its two main military powers, and could face calls for similar votes by anti-EU politicians in other countries.

Gold in terms of sterling and euro surged to the highest since April 2013.

U.S. crude was down $2.71, or 5.4 percent at $47.40 a barrel and Brent oil slid $2.68, or 5.3 percent, to $48.23 a barrel.

London copper was off 3 percent at $4,636 a tonne, after touching a seven-week top of $4,795 on Thursday. Nickel fell 4 percent and zinc dropped 3 percent.

In China, rebar futures slipped 0.4 percent and iron ore was up 0.1 percent.

(Reporting by Manolo Serapio Jr.; Editing by Ed Davies and Joseph Radford) ((manolo.serapio@thomsonreuters.com; +632 841 8972; Reuters Messaging: manolo.serapio.thomsonreuters.com@reuters.net Twitter: @MannySerapio))