The banners are going up at San Francisco’s Yerba Buena Center.  The tech media is in a lather of frenzied anticipation. It can only mean one thing – the announcement of Apple’s new iPhone handset.

The official unveiling doesn’t come until Wednesday afternoon but the industry has been rife with rumours and speculation. As a result, for those of you contemplating an upgrade to an iPhone 5, we can tell you what the new handset is expected to offer, even if we can’t confirm the exact details until Wednesday.

1. A Bigger Display

Rumour has it that the new iPhone will follow the trend for larger screens – upgrading from the existing 3.5 inch display (as measured from corner to diagonally opposite corner) to 4 inches, with a 1136x640 resolution.

However, it seems Apple is wedded to the current iPhone’s width (some consumers aren’t so keen on wider handsets like the Samsung SIII), so the larger display will be achieved by making the phone longer rather than wider.

2. Slimmer and Taller

The speculation is that the iPhone handset will be up to 30% slimmer than the current 4GS model , and taller, as mentioned above, to incorporate the bigger screen.

However, those of you hoping to employ your existing Apple accessories may be distressed to  learn that one sacrifice of this new, slimmer handset is likely to be the existing 30 pin jack, which is likely to be replaced by a more ‘petite’ 9 pin offering.

3. 4G Connectivity

4G is the name for the new superfast networks being rolled out by the network operators. Or to be more precise, being rolled out by Everything Everywhere (or EE, a combination of T-Mobile and Orange) over the next few months – the other networks are lagging at least 12 months behind.

If the new iPhone offers 4G connectivity, and that connectivity is configured to work in the UK (which is likely), the rollout of EE4G will mean that Chitter Chatter customers will be able to benefit from browsing speeds of up to 100MBPS over the coming months, up to 20 times faster than existing 3G networks. Better still, with the other networks lagging so far behind, only EE customers will be benefit from these superfast speeds. Exactly how jealous are your friends are going to be?

Those of you hoping for iPhones in a rainbow range of shades are likely to be disappointed – the iPhone 5 is only likely to be available in white or black - as are those who were hoping for the mobile payment technology NFC to be incorporated. The likelihood is it won’t.

And there’s been little hearsay on what sort of upgrade the cameras will have – although a re-design and upgrade is certain if the phone becomes thinner – and what sort of spec the battery will be. The rumour is that it will be bigger, but the increased size may be required to power the bigger screen without necessarily delivering a longer life between re-charges.

And, of course, it’s likely the processor will be faster and more powerful – but how much faster and more powerful, we have no clue.

As is the norm, the iPhone 5 will likely be available for purchase within a few weeks of its launch. And if you’re interested, you’ll need to get a wriggle on – according to research, 21% of the UK population are considering upgrading to one!