Premier Jason Kenney's principal adviser David Knight-Legg spent thousands of taxpayer dollars during four trips to London, U.K., Alberta's Official Opposition said Wednesday.

The NDP highlighted the expenses in a news release based on publicly available travel and expense disclosures.

Harrison Fleming, deputy press secretary with the premier's office, said one of Knight-Legg's tasks is to secure capital investment for Alberta — especially for the energy sector, but also for artificial intelligence and technology.

"This obviously includes meetings with companies and investors to sell the merits of Alberta," Fleming said in a written statement. "Albertans hired this government to bring back the job-creating investment that this province needs to get folks back to work."

According to the disclosures, Knight-Legg spent more than $18,000 on four trips to London in the last six months. He stayed in upscale hotels such as the Chilworth London Paddington.

Knight-Legg also billed Albertans for Uber rides, train tickets and meals, the disclosure documents show.

In total, he has claimed nearly $45,000 in expenses since the United Conservative Party was elected, according to the documents.

Knight-Legg earns about $195,000 a year.

According to the province's expenses policy , which was last updated in 2015, claims should be accepted by Alberta's auditor general and the public, properly documented and explained, reasonable and appropriate.

Fleming said Knight-Legg's expenses are in line with the policy. He said Knight-Legg stayed in or near London's financial district, so he could host meetings with investors at his hotel.

"Hotel costs in London are in the range of £200 to £300," he said, equal to roughly $340 to $510 Cdn.

The rates are "not abnormal in an expensive, global city like London, and consistent with government-approved rates," Fleming said.

Edmonton NDP MLA Heather Sweet said the trips weren't necessary.

"Neither the premier nor the [minister of trade] were attendants of these meetings," Sweet said.

"These meetings should have happened over the phone or Skype instead of having this individual do four trips to London without any member of cabinet."

"This premier is cutting services in AISH [Assured Income for the Severely Handicapped], seniors' drugs, schools, hospitals, and yet it's OK for his people to spend a ton of money," she added.

Sweet said the government needs to disclose more details.

"We haven't actually seen the itinerary of what he was up to in London," she said.

Fleming said Knight-Legg travels to meet with major banks, private equity funds and insurers.

The organizations he meets with can't be named "due to the commercially sensitive nature of the meetings," Fleming said.

"Foreign-funded activists' groups are actively targeting Alberta and large companies doing business in our province."

In a news conference Wednesday in Calgary, Kenney said he has sent his staff to meet with global companies in London and Europe.

He also said he plans to visit London in December to meet with global investors.

Kenney spent over $16,000 in public funds to fly three other premiers from Calgary to the Council of the Federation meeting in Saskatoon last July.