Negotiations between the UK and European Union over British withdrawal-Brexit-will determine whether the cost of UK trade in oil and gas goods rises or falls.
The trade group reported study results a month before an election that will determine how negotiations proceed.
Prime Minister Theresa May called the election for June 8, saying she wants a victory to strengthen her hand in the EU exit talks.
She replaced David Cameron without an election after he resigned in response to the June 2016 referendum supporting Brexit. Complex negotiations with the EU are to be completed by March 2019 unless the EU extends the deadline.
May mildly opposed Brexit before the referendum but now supports it as the expressed wish of a voting majority.
The election next month doesn't address Brexit directly. A political party beating May's Conservatives and opposed to Brexit would have to call a new referendum.
Not all opposition parties want that. But a Conservative loss at least would change British negotiating priorities.
For the cost of oil and gas trade, implications are large.
At present, according to the Oil and Gas UK study, the cost of trade in oil and gas goods exposed to tariffs amounts to £600 million/year-less than 2% of the total value of trade subject to tariffs.
At this writing, the British pound was worth about $1.30 (US).
If the UK reverted to World Trade Organization rules with the EU and rest of the world-a condition described by the study as "a worst-case scenario"-the likely cost of oil and gas trade would jump to £1.1 billion/year if trading behavior didn't change.
Negotiation of "minimal" tariffs with the EU and "improved" tariffs with the rest of the world, however, might lower total trade cost to £500 million/year.
In a letter on study findings to May, Oil and Gas UK also expressed concern about possible limits on labor movements, which now are unrestricted.
The group takes no position on Brexit.
