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No it is not suitable for mains voltage.
In the data sheet available from the URL you posted
It shows that it is a simple LED and the polarity is defined in the mechanical diagram.
The LED characteristics for the product range are detailed in the table at 20mA so will need to be driven from a current source/dropper resistor.
@RS Components Support The datasheet referenced makes it look like this is suitable as it says contact rating 250VAC. The product data on the RS website also states AC Voltage Rating 250V
@davecole Yes you are correct as was the OP that the contact ratings are suitable for 250V AC. From Spec. CONTACT RATING: 500mA 48VAC-200mA 50VDC-200mA 250VAC The LED is addresses separately further down the data sheet on page 3 with LED voltage at 20mA drive, the pin out on page 4 also shows the +/- pin orientation of the LED. The datasheet and RS page could be made clearer in this respect and the user may wish to feed this back to RS Components using the form https://uk.rs-online.com/web/feedback.html or the "Product Support Team" https://uk.rs-online.com/web/generalDisplay.html?id=our-services/product-support