Sharecast - At 0910 BST, the FTSE 100 was down 0.3% at 7,884.96.
Susannah Streeter, head of money and markets at Hargreaves Lansdown, said: "Caution is in the air ahead of the results from big tech rolling in, and the latest snapshot of US consumer confidence."
"Investors are assessing the extent to which nervousness about what may lie ahead for economies is holding back marketing budgets and delaying purchases by shoppers. The FTSE 100 has taken a more downbeat cue from trading in Asia and has opened lower with mining stocks under pressure, as concerns swirl about lower demand for commodities."
On the macro front, figures released earlier by the Office for National Statistics showed that government borrowing continued to rise in March, partly due to the energy support scheme.
Public sector net borrowing came in at £21.5bn, slightly above expectations of £21.3bn and up £16.3bn on March 2022. It also marked the second-highest borrowing figure since monthly records began in 1993.
Meanwhile, borrowing for the financial year ending 31 March was estimated at £139.2bn - up £18.1bn on the previous year and the fourth highest since records began. The figure represents 5.5% of GDP.
Chancellor Jeremy Hunt said: "These numbers reflect the inevitable consequences of borrowing eye-watering sums to help families and businesses through a pandemic and Putin's energy crisis."
"We were right to do so because we have managed to keep unemployment at a near-record low and provided the average family more than £3,000 in cost of living support this year and last."
"We stepped up to support the British economy in the face of two global shocks, but we cannot borrow forever. We now have a clear plan to get debt falling which will reduce the financial pressure we pass onto our children and grandchildren."
In equity markets, miners were among the worst performers, with Rio (LON:RIO), Glencore (LON:GLEN) and Anglo American (LON:AAL) all down.
Primark owner Associated British Foods (LON:ABF) was also down after it reported lower interim profits as the clothing retailer and foods group battled inflationary headwinds and lower consumer spending amid the cost-of-living crisis. It posted adjusted operating profit of £684m, down 3%, for the 24 weeks to March 4. Primark profits fell to £351m, compared with £414m a year earlier.
On a pre-tax basis, AB Foods' earnings for the period rose 1% at £644m, supported by a 23% rise in profits at its foods and division. The firm expects full-year profits to flat, in line with guidance.
Builders merchant Travis Perkins (LON:TPK) was weaker as it held annual guidance despite a tough first quarter as the house building market stalled and property renovation and maintenance was deferred.
On the upside, Premier Inn owner Whitbread (LON:WTB) rallied after saying that full-year earnings had soared above pre-pandemic levels on the back of strong demand for hotel rooms after the lifting of COVID-19 travel restrictions and unveiled a £300m share buyback.
The company, which also owns the Beefeater steakhouse chain, reported pre-tax profit of £375m, up from £58m a year ago and £218m in 2020 before the pandemic shut down the leisure and hospitality sectors.
Eurowag (LON:WPS) gained ground after a well-received first-quarter trading update.