By Sarah Young

LONDON (Reuters) -Marks & Spencer will be over the worst of the fallout from this year's damaging cyberattack by August, its CEO said on Tuesday as shareholders questioned the British retailer over whether it could have prevented the incident that caused a 300 million pound ($413 million) hit to profit.

The April attack on M&S, one of the biggest names on UK shopping streets, forced the group to close its online store for nearly seven weeks and led to empty shelves at its shops during May as automated stock systems were shut down.

"I'm really hoping by August, the majority of this is behind us," CEO Stuart Machin told shareholders at the company's annual meeting, their first chance to press the company publicly on the attack and its consequences.

Asked whether the attack could have been stopped, Chairman Archie Norman said there was always something that could be done and M&S continued to examine the incident.

Machin emphasised how M&S had quadrupled investment in cyber security and trebled the number of colleagues working on protecting its systems over the 12 months before the attack.

"I'm glad we invested then. I'm glad we continue to invest," he said.

One investor asked whether Machin's bonus should be cut because the cyberattack happened under his watch. Norman said the group's philosophy was to adjust incentive pay to reflect shareholder rewards but it was too early to say how that might look this year.

Machin's total pay package in the company's past financial year jumped 39% to 7.1 million pounds.

He said the focus now was on recovery and strengthening training to help staff guard against the type of social engineering that allowed hackers into M&S systems via a third-party contractor.

M&S's online shop is still only partially open but is expected to be fully restored within the next four weeks, Machin said. The company had warned in May that there would be disruption to online services until July.

Internal systems including automation at its Donington logistics warehouse are expected to be back up and running by August, Machin said.

($1 = 0.7272 pounds)

(Reporting by Sarah YoungEditing by David Goodman)