27 March 2014 Last updated at 18:42

Microsoft unveils iPad Office suite

By Leo Kelion Technology reporter

Microsoft's new chief presented his first launch in San Francisco

Microsoft has started offering an iPad edition of its Office software suite.

It was announced at the first launch event hosted by Satya Nadella since he became chief executive of the firm.

The productivity suite - including Word, Excel and Powerpoint - has been optimised for touch-based controls to make it easier to use than the web-based alternative already available to the tablet.

The firm has faced criticism for not offering the software until now.

Mr Nadella said that the announcement was part of a strategy to empower people "to be productive across all devices" with Microsoft software.

"We are taking great focus and great care to make sure Office on any device shines through," he said, indicating that his firm would release versions of the apps for other mobile devices in the future.

Research firm Gartner predicts about 271 million tablets will be shipped this year - only slightly less than its forecast of 277 million PCs and laptops - and Apple's iPad is currently the bestselling model.

Mr Nadella's predecessor, Steve Ballmer, launched an iPhone version of Office last year and confirmed an iPad version was in the works.

Microsoft said that Office allowed users to create "sophisticated" page layouts by touch

But many industry watchers have speculated that Mr Ballmer deliberately delayed its release in order to debut a tablet touch-centric version on Microsoft's own Surface machines before bringing it to a competing platform.

App rivals

Office remains Microsoft's cash cow, accounting for $16.2bn (£9.7bn) - or just over 60% - of Microsoft's operating profit in its last financial year. But some believe that sum could have been larger.

"It was definitely a major mistake to wait - an example of the insular old-world thinking of Steve Ballmer and his management team that believed everything should be within a Windows ecosystem," said Chris Green, from the Davies Murphy Group consultancy.

"In today's multi-device environment, where Windows is no longer the all dominant platform it once was, that game plan doesn't work anymore. The fact Microsoft is now catching up is only going to be a good thing and will be to the benefit of the Office applications."

Rival apps such as HopTo already exist to let users edit and share Office documents

The iPhone version has attracted a relatively low review score from Apple's App Store users, many of whom complained about its cost - it required an Office 365 subscription sold for £80 a year - and missing features.

Meanwhile other apps - including Documents to Go, HopTo, Quickoffice, Google's business web apps and Apple's iWork suite - have prospered offering free or cheaper alternatives that can load and alter files originally created by Office.

Some critics have questioned whether Microsoft has left it too late to act.

However, the iPad edition is more powerful than the original iPhone version - for example more complicated edits can now be made to Powerpoint presentations and the programs make recommendations to help create visually appealing documents - and several experts believe there will be strong demand for the product.

Freemium model

Users wanting to only view and present documents can use Office for iPad without charge, but an Office 365 subscription is needed to edit them.

"Much as you can edit Excel spreadsheets and tweak Word and Powerpoint documents with other software, it can involve technical gymnastics and be a great pain on an iPad," Richard Edwards, an analyst at tech research firm Ovum, told the BBC.

"Often when you move from one program to another the DNA of a document gets twisted and distorted, with formatting errors and other problems.

"For the reduction in stress people and businesses will be more than willing to pay for the subscription cost."

A laser-like graphic shows where the user's finger is pointing when an iPad running Powerpoint is linked to an external monitor

However, one analyst said the Mr Nadella still had more work to do to reassure shareholders.

"The company's announcement today around offering Office for iPad - and eventually other devices - will be warmly welcomed by investors, in our view, as it adds a long awaited gateway to enterprise users, finally capitalising on bring-your-own-device-to-work trends," said Daniel Ives from FBR Capital Markets.

"[But] reinvigorating the Windows franchise continues to be a key ingredient in Microsoft's recipe for success.

"With the much-hyped Windows 8 having experienced lacklustre adoption, we believe investors will be looking for hints or previews around Windows 9 and subsequent updates to Windows 8.1 at the upcoming Build Conference as this struggling high-margin business remains front and centre."

Microsoft's Build conference for developers runs from 2 to 4 April in San Francisco.