LONDON -- April will start off quite slowly for company news, but things will pick up around the middle of the month. There will be updates from a good few FTSE 100 companies, and we'll keep you updated on them as the month progresses. But in advance, here are five of the most important diary dates.

April 11: Marks & Spencer (MKS -0.04%)
Marks & Spencer will be bringing us a fourth-quarter update on the 11th, shedding light on how the year to March 31 has gone -- full results will be with us on May 21. The share price got a bit of a boost last week to 395 pence on rumors of an 8 billion pound bid in the offing from the Qatari Investment Authority, but other than that the shares have had a pretty lamentable few years.

Forecasts suggest a 7% drop in earnings per share, putting the shares on a price-to-earnings ratio of 12, with a nearly twice-covered dividend yield of 4.3%. With modest earnings and dividend rises penciled in for 2014 and 2015, the P/E would fall to 11 and 10.5, respectively, while the yield would rise to 4.5% and then 4.8%.

April 17: Tesco (TSCO 0.60%)
Full-year results from Tesco are due on the 17th after what has been quite a tumultuous year. The share price famously slumped in January 2012 after the U.K.'s biggest supermarket reported a weak Christmas trading period. But since about October, the price has been steadily rising, reaching 378 pence today.

And this time around, things looked better over Christmas and New Year, with U.K. like-for-like sales up 1.8%, and the company reported "recovering in-store performance." Forecasts for the year to Feb. 28 put the shares on a P/E of 12, with a 4% dividend yield.

April 24: GlaxoSmithKline (GSK -0.88%)
It's time for first-quarter figures from GlaxoSmithKline on the 24th. The pharmaceuticals giant reported flat earnings for the year to December 2012 but lifted its total dividend by 5.7% to 74 pence per share for a yield of 5.5%. At the time, chief executive Sir Andrew Witty told us the firm expects 3% to 4% growth in core EPS for 2013, along with "further strong cash generation," which should support increasing dividends.

Analysts are forecasting a 5.4% boost to this year's annual payment, which would provide a yield of 5.2% on a share price of 1,506 pence -- and that's significantly above the average FTSE 100 dividend of around 3.1%.

April 24: Barclays (BARC 1.28%)
Barclays will also deliver first-quarter results on the 24th, continuing on from a strong performance in 2012, when the high-street bank reported a 24% rise in EPS and the fourth annual dividend raise in a row. After the 2009 payment was slashed to just 2.5 pence per share, it has crept back to 6.5 pence last year, with about 7.25 pence currently forecast for 2013. With the shares currently changing hands for 287 pence, that would be a yield of 2.5%.

And that 287 pence share price is up 90% since last July's low (and it has been even higher, exceeding 320 pence in February), but even after that, the shares are still on a forward P/E of less than eight.

April 30: BP (BP -0.95%)
It's BP's turn to deliver first-quarter figures on the last day of the month, and a lot of people will be eyeing up the oil giant's cash situation. After disposing of assets over the past couple of years to help meet the costs of the Gulf of Mexico disaster, BP announced last week that it will embark on a share buyback program worth up to $8 billion. That amount represents the cost of its original 50% stake in TNK-BP, which it has just sold to Russian state oil company Rosneft for $12.5 billion.

The shares have not moved much over the past couple of years, standing at 463 pence as I write, and they're currently on a P/E of just 8.2 based on forecasts for the 2013 full year.

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