UPDATED: 10:45 a.m.

As expected, Gov. Bob Mc­Don­nell announced Wednesday that he had vetoed a bill that would raise awards in medical malpractice lawsuits $50,000 a year starting in 2012. He told legislators it violated a campaign promise he made.

“Raising the cap for medical malpractice judgments to $3 million over the next twenty years, without further reforms in the medical malpractice litigation system, will not meaningfully protect against health care cost increases,’’ Mc­Don­nell said in a statement. “While I commend the affected stakeholders for working diligently together, increasing the medical malpractice cap will ultimately lead towards higher health care costs for doctors, hospitals, businesses, and most importantly, patients.”

The General Assembly is expected to attempt to override the veto when lawmakers return to Richmond next week. Legislative leaders had previously warned Mc­Don­nell that the legislature so overwhelmingly approved the bill that both chambers could override a veto. The Senate passed the bill unanimously while the House of Delegates approved it 89-7.

Lawmakers have debated for years whether to increase the awards in medical malpractice lawsuits. Some Democrats have favored an increase, but Republicans have rejected the proposals in the name of tort reform.

McDonnell, a lawyer and former state attorney general, favored some increases when he was a legislator, but criticized his Democratic gubernatorial opponent, Sen. Creigh Deeds, for supporting a 1999 bill that would have raised Virginia’s cap on medical malpractice settlements from $1 million to $3 million.

And an increase likely would not play well for Mc­Don­nell, who is eyeing a role on the national stage.

A trio of organizations had negotiated a compromise — the Medical Society of Virginia, the Virginia Hospital and Healthcare Association and the Virginia Trial Lawyers Association — and been lobbying the governor to sign the bill. They sent a joint letter to Mc­Don­nell, and encouraged others to do the same.

Del. David Albo (R-Fairfax) and Sen. Henry Marsh (D-Richmond), both attorneys, helped trial attorneys and doctors negotiate a deal before this year’s legislative session began by telling them that if they didn’t work out a compromise, legislators would do it for them.

In the 1970s, the General Assembly capped awards in medical malpractice lawsuits at $750,000. The cap was gradually increased and capped at $2 million in 2008.

The bill calls for an increase from $2 million starting in 2012, and then $50,000 each year until 2031.