Indian carmaker Tata Motors on Wednesday reported a 42 percent rise in quarterly profits, buoyed by a one-time gain from changes it made to pension plans at British unit Jaguar Land Rover.

Consolidated net profit for the three months through June rose to 31.82 billion rupees ($498.73 million) compared with 22.36 billion rupees a year earlier, the Mumbai-based company said in a statement. 

The auto major beat earnings forecasts. A Bloomberg survey had pegged net profit to come in at 14.80 billion rupees for the quarter.

Tata Motors said it benefited from changes it made to Jaguar Land Rover's pension plans which gave it a one-time gain of 36.09 billion rupees. 

Revenue fell about 10 percent to 599.72 billion rupees. 

Jaguar Land Rover, one of Tata Motors' key units, saw a 14 percent drop in sales in its UK home market but witnessed 30 percent growth in China. 

"While the first-quarter results have not met our expectations, we are working with renewed focus and energy to improve performance of our Commercial and Passenger Vehicle businesses," Tata Motors chief Guenter Butschek said in a statement. 

JLR retail sales were up 3.5 percent, with 137,463 units sold for the quarter ending June, the company said. 

Sales of commercial and passenger vehicles were down nearly 12 percent from a year earlier.

Tata Motors has been hit by a weak pound following Britain's vote to leave the European union. 

Since the "Brexit" referendum sterling has fallen sharply against the Indian currency, down from over 100 rupees to 82.94 on Wednesday.

Shares in Tata Motors, part of the sprawling tea-to-steel conglomerate, fell by 3.17 percent on the Bombay Stock Exchange.