* Q2 net profit before tax $2.5 bln
* Bank avoids fresh legal and conduct charges
* Interim dividend of 2.5 pence per share, above expectation (Adds share price performance, outlook)
LONDON, Aug 2 (Reuters) - Barclays second-quarter pretax profits almost trebled, beating analysts' expectations as the British bank avoided the heavy restructuring and legal costs that blighted past results.
Barclays reported pretax profit of 1.9 billion pounds ($2.5 billion) for the April-June quarter, up from 659 million pounds a year ago and higher than the 1.46 billion average of analysts' estimates compiled by the bank.
The bank said it would pay an interim dividend of 2.5 pence per share, above analysts' expectations and above the 1 pence paid at the same time a year ago.
The results showed signs of promise for long-suffering Barclays investors in the underlying profitability of the lender, as Chief Executive Jes Staley battles to grow revenues and push back against calls to prune its investment bank from activist investor Edward Bramson.
"It is the first quarter for some time with no significant litigation or conduct charges, restructuring costs, or other exceptional expenses which hit profitability," American CEO Staley said in a statement.
"It is the first clear sight of the statutory performance of the business which we have re-engineered over the past two and a half years - Barclays transatlantic consumer and wholesale bank - and it is a positive sight," he said.
Barclays shares initially rose as high as 2.5 percent, but were down 0.6 percent by 0728 GMT, as investors reflected on the fact that the huge second quarter improvement was more the result of fewer fines, smaller restructuring costs and bad loans than from improved income.
Income in the lender's under-pressure investment bank rose just 1 percent in the first half of 2018, largely due to outperformance in the equities division, where revenues rose by 30 percent.
In the second quarter itself, divisional income rose 2.7 percent to 3.7 billion pounds.
The underwhelming income result, teamed with continued worries about costs has failed to quell debate over the future of Barclays' investment bank, which Bramson wants to shrink.
The New-York-based financier disclosed a surprise 5 percent stake in Barclays in February, and has argued in presentations to his investors that the lender should pare parts of the investment bank that do not directly serve corporate clients.
"We are in conversations with Bramson, I have met him, and we look forward to meeting him post these results, but he has not outlined what his strategy is to us," Staley told reporters on a conference call.
Barclays' core capital ratio, a key measure of financial strength, rose to 13 percent, just above analaysts' average forecast of 12.9 percent.
That number had been depleted by fines and misconduct costs and was a source of concern for investors in recent months, fueling speculation the bank might need to raise fresh capital.
Barclays still faces a raft of problems that threaten to dent its numbers in future.
The UK's Serious Fraud Office is seeking to resurrect its prosecution of Barclays over undisclosed payments to Qatari investors, and the bank faces a host of investigations into interest rate manipulation and its conduct in foreign exchange trading. ($1 = 0.7632 pounds) (Editing by Sinead Cruise/Keith Weir)